Well theres alot to consider. Are the kids actually at fault? Sometimes the difference in COD vs intact situations is that the kids have a place to run to if they dont want to follow rules. Intact families the kids just have to suck it up and deal because theres no other house to go to. SM might just be the scapegoat.

Also, 2 of the kids are very close to leaving home age. Is it worth losing your partner when the kids are almost out of the house anyway? 

Their problem with my wife stems back about 5 years ago where she let extreme negativity from my ex-wife affect the way she treated my children

How did/does your wife treat your children? Can you objectively say that she did or didn't treat them badly and create a toxic environment?

I know that my husband would never have put up with me treating his daughter (now, 28) badly, especially just because I didn't like his ex-wife. I was the adult, I would have never taken BM's negativity out on my SD.

Across these same years my wife has developed a dislike for my children and cites disrespect and lack of a voice in her own house

How have your children treated your wife? Again, can you look at it objectively?

Frankly, when you use the word "venom" regarding your wife, it doesn't put her in the best of light and makes me feel bad for your kids.

If your children are happier living with their mother then perhaps that is for the best. You can explain to them that people make mistakes and that you could have handled the home situation better but that you care about them and want them to be happy where they live. The majority of kids leave home at some point anyway, these children are just leaving your home a little earlier. You can still have a realtionship with them while they live with their mother and beyond that into adulthood. If the relationship between them and your wife is severly damaged right now then keep them all apart. See your children outside of your home and away from your wife. 

Accept that all of the adults involved played a part in this situation, you, your wife and your ex. Children learn disrespect when they are taught it and not set straight by others when they start to show disrespect. Being a step parent can be tricky and your wife may have let her emotions about adult issues seep through, you seem to also have failed in a large extent to insist on children behaving properly in your home and your ex seems to have fed the children her negative views of your wife (and possibly you). The children are partially at fualt but mostly it is all of the adults around who have moulded them that way. If, as they grow and mature and move out into the world, they continue to display the same behaviors then they will have to face thier own responsibility for their actions.

To move past this with your wife removing the children is only part of the solution. You both need to accept your portion of responsibility for what got you to this point. You need to start understanding one another better, communicating better and sticking up for each other and your relationship. A good therapist will help you two to work through all of this. 

If you do not want to accept your part in all of this, do not want to try to save your marriage, or do not want to face not having your children visit your home then leaving is probably the only option that you are left with.

There aren't enough facts and examples here to really determine what is going on, but just making assumptions, it doesn't reflect well on you and how you handled this.  Negativity from your ex-wife should not have been allowed.  Disrespect from your children should have been nipped in the bud.  Your wife should never be made to feel that she lacks a say in her own home.

Do you love your wife?  Do you want to spend the rest of your life with your wife?  If the answer is yes, get thee to marriage counseling as soon as possible.  And unless you can honestly say that your wife is mistreating your children and there is not a good reason for it (i.e, your kids also treating your wife badly), I would allow the two older children to go live with their mom, but I would do everything in my power to continue a relationship with them by seeing them regularly, taking them out to lunch or dinner, attending their events, etc.  You don't say what the custody arrangement is now.  Are they living with you full-time, do they come EOWE, or is it something in between?  I don't think it's necessarily true that allowing them to go live with their mother means you will lose them.  As  they get older they'll gain some perspective.  It is not uncommon for teens to make boneheaded decisions and later reconsider them once they mature.  There's no guarantee of that, but it's practically guaranteed that if you choose your kids, you've lost your wife.

More info needed - what was your ex-wife doing? Was she trying to turn the kids against your current wife and her kids? Were your kids rude to your wife and her kids? Why did she decide that she did not want all the kids to be together?

Do you discipline your kids? Do you allow them to make all decisions and take their side if you wife doesn't want them to do something? Do they help around the house? Do you elevate them to adult status and see no flaws in their behavior whatsoever, putting all the blame on your new wife? Does she take her "venom" out on you because you don't parent them properly and she's left cleaning up after them and being miserable when they are there?

If your ex-wife's goal was to turn the kids against your new wife, she might have succeeded. But it's hard to know what's going on without more info. 

I dont think anyone can really tell what to do, without knowing all the facts.  Did you wife make your kids life miserable becuase of custody disputes? 

Do you coddle your children and put them first, above all else?
Do you and your children treat your wife with respect and dignity?
Do you confind in your children about issues and fights you and your wife have?
Do you defer to your children when it comes to making important decisions?
Do your children hurt or belittle your wife in front of you and you say nothing?

If you can answer yes to one or more of those questions, then you need to take a good hard look at yourself and your parenting style.

Can you tell us more about why your wife feels disrespected and has no voice in her home? That's not an unusual feeling for stepmothers, and maybe her feelings are entirely justified. And maybe she is a hateful witch who is impossible to live with. Some examples would help.

You are being blamed for something. 

No one appears to have issued you ultimatums (ie the threat that they will never speak to you again, is the usual classic line).

This is the life you have at present. You need to find solutions, instead of possibly overdramatising stuff in your head.

Let your kids adjust to being with their mum, whilst maintaining the best relationship you possibly can with them. 

You can always attempt to renegotiate at a later date once the dust has settled, and possibly had counselling. 

Ahhhhhh, it's all craziness. Genepools aren't meant to be blended. I believe that humans are wired differently than to take in offspring that aren't theirs.

Yes, your kids left because they don't like your wife. Is it your wife's fault though? I'm going to say no. It's her house, her rules, just the same as it's your house - your rules. She's permissive of her own children because, well, they're her children. Yours are not. 

What's unfair about your situation is that YOU also have to tolerate HER kids. Disengage from her animals, and see if she offers you the same courtesies that you're offering her. If she does, and her kids end up leaving because you ain't Daddy, force the same expectation she has OF you onto HER.

That's my honest opinion. Men and women with kids already can't have their cake and eat it too. If they bring monsters in, they also have to be willing to tolerate monsters. (Or kick the monsters to the other parent). 

I feel it's going to be very different.  If he giving some fault to the EX I am sure there more to it. 
you mus decide if you want a happy marriage, or live with your kids.  You now can not have both. Just remember on those cold night where you would be sleeping.  Wife, or yourself.   If you let your kids win, you will never have another relationship they will control your life 

You all screwed up the relationship and didn't/couldn't fix it. Put a bullet in your marriage, not because your kids are "making" you, but because it's a bit of a sham at this point. Then work with your own kids to make sure they are respectful and civil no matter who they are around.

This isn't kids versus wife. Your relationship with your kids needs to be fixed and you need to parent them better if they are, indeed, disrespectful. Your relationship with your wife is a dumpster fire that you two can't fix with help. The only solution is cut your losses and deal with your responsibility to raising kids who won't be a-hole adults.

This isn't that hard to figure out.

You've been to marriage counseling twice. You've tried family therapy. You and your wife are both in individual therapy.

And yet you come to a bunch of strangers on the internet to seek advice? Why? Either all your therapists have all been terrible or you lack decision making skills (or fortitude).

I wish you all the best, I really do.

Oh my gawd, time to pull the plug on this marriage. I really really really don't think it's going to work out.

OP, you still haven't answered the questions. HOW did your wife treat the kids that they are so stressed by? How did THEY treat HER?  Was she just the unreasonable evil stepmother or did they treat her badly? Did you parent them or let them get feral which stressed your wife? What did your ex-wife do to help turn them against your wife?

You haven’t addressed what happened ‘when you spent a year out of the house’. 

did you separate for a year, or did you both have two separate houses and still see each other? Eg her and her kids/ you with yours, so everyone got a break. 

What went wrong? 

Sometimes kids do go and stay at mums most of the time. That’s what happens when parents separate, it’s not nice, but that’s life. 

Sometimes instead of constantly trying to change things we have to accept what is on the table so to speak and just get on with it. 

I actually think your kids would have moved out no matter who you were with, as someone pointed out earlier teenagers are always unhappy for one reason or another. 

Accept and adjust, rather than trying to keep (or get back) what you had. 

I think you don’t want to acknowledge that you you had a problem setting boundaries for your children, and when someone tried to set boundaries the kids were upset they couldn’t rule the roost and just went somewhere where there is less rules.

I agree with so many of the other posters here that it appears you placed your children over your marriage.  It would be interesting to know why you married your wife in the first place, and what your expectations were for her.  I really think many DHs marry women whom they assume will take over as a Mother rather than a wife.

In another post the Evil put forth the idea that many parents place their children as their top priority in their fist marriage which could be the reason for the failure of that marriage.  I know now (a little late) this was at least part of the reason DH chose to marry me.  The difference was, I didn't have the same rights as BM.  I was to merely play the role - smile, sacrifice and stay quiet.  SD had a completely different agenda.  She didn't need another Mother.  She already had a Mother who didn't want to share the job.  Instead, I was an obstacle to her relationship with DH.  This leaves a SM juggling on the high wire.  The 'bonus' for DH and skids is that NOW they have a handy scapegoat they can blame everything on.

You wrote that you are at a breaking point.  But I've got news: There's nothing to break when you weren't 'together' in the begriming.  The dead give-away was in your second sentence when you referred to your "remarraige" rather than "marriage".  In the last paragraph you wrote, " I believe I have hit MY breaking point--" instead of "WE are at OUR breaking point." This speaks volumes..

You obviously value your children - and BM - far more than this woman whom you 'chose' to 'remarry'.  Please do this poor woman a favor and let her go on to live a happy life without trying to live up to the unfair and unrealistic expectations you have placed upon her. 

Maybe he’ll really like this quote too:  “You wrote that you are at a breaking point.  But I've got news: There's nothing to break when you weren't 'together' in the beginning."

You are doomed to repeat this scenario with another.  Despite your wording "venom" and a bias towards blaming your current wife, i don't necessarily see much that shows that she is unreasonable.  The fact that she doesn't feel that she has a voice in her own house is a huge problem and I believe that you have participated in allowing this to happen.  It's clear to me that you don't empathize with it enough to take responsibility to ensure that she does feel heard.  

You can blame her, start over and rebuild your relationship with your kids.  Maybe wait until they hit college and start again.  Or try again before then.  But considering that you don't seem to have a handle in your responsibility in your wife not feeling heard, you are probably going to make the same mistakes.

Well, IMHO the facts are that you have failed your wife, you have failed your marriage, you have failed your children and you have failed yourself.

So, at this point you have little choice but to choose yourself and let both you wife and your children know that you are done with tolerating crap from any of them.  Inform your wife that her irrational hate for your children will no longer be tolerated and inform your children of their own contributions to the situation and their crap will not be tolerated.  You should have shut your XW up long ago rather than tolerate her toxic crap that offended your bride and polluted your children.

Neither your wife nor your children are without fault in all of this and YOU are the common denominator. You should never have allowed your toxic and shallow gene pool to destroy your bride's happiness.  Shame on you.

You have a ton of work to do to salvage your marriage, salvage a relationship with your children and to make a tolerable life for yourself.

Be prepared for the single life and to be estranged from your children wich is the most likely outcome at this late stage of the game.

Good luck.

I just recently left my fiancé. He chose his kids over me. Not directly of course. But by choosing to allow them to disrespect me, he left very little room to stay with him. After 2.5 years of taking care of his small kids, having my schedule changed last minute because of his ex, feeling invisible when his kids were around and finally, enduring disrespect from him and his children, I left.

so before you go choosing your kids over the woman you CHOSE to bring into your life, just know one thing:

this scenario with your wife will play over and over again with future partners you choose until you die, a lonely old man. After all, no one is their mom.

good luck!!

Maybe I haven't been reading every single post with a fine tooth comb, but I haven't got the impression that you really love your wife anyway. Correct me if I'm wrong, but I haven't seen you say "I love my wife very, very much ".  I did see you write that you respect the sanctity of marriage. But that's it. 

You have given your kids way too much power in the household. Your wife does not sound nasty nor abusive in any sense. Fed up? Disengaged? Yes and justifiably so. Congratulations on another failed relationship.  You have also taught your children they call the shots in the process and have way too much power. Your ex, your lack of boundaries and your lack of parenting are also reasons why your kids behave this way. If you tolarate your ex's and kids crap they will continue with their crap because they know they can get away with it.