So I know that when we end up on this site, we've hit a wall, but nothing about your relationship sounds good here. It sounds like your partner doesn't contribute financially, and in fact you foot the bill for his children's visits. He doesn't meal plan or do things that are proactive about chores, which is wild if he's unemployed because you shouldn't be working all day and coming home to someone who's been home all day but who hasn't washed a dish or prepared a meal. And he doesn't prioritize you physically or emotionally. And I'm glad he doesn't ask you to babysit because dang, he's home all the time already! And it sounds like he's obsessed with spending every second with them. Also, I want to point out that it's wild that the KIDS are saying "hey, we miss you at night". NOT YOUR DH. He's not the one saying "I really want to have a movie night with the kids when they're here, but I'd love it if you'd snuggle up with me". What is the appeal of this man???

I'm glad you've already communicated that you have to go to counseling, because you HAVE to, and your partner has to show genuine change, and you have to have boundaries you will stand by. If he needs to make dinner Tuesday and Thursdays, then that's his responsibility. Don't cave and end up doing it for him. And he can totally set reminders on his phone or something! If you weren't married, what would he do? He'd remember he needed to cook dinner eventually! He needs to contribute to both your household and your marriage, because right now it doesn't sound like he is living up to his end of the bargain. 

I would also suggest counseling. He doesn't sound like he's being a good husband. It would be one thing to roll out the red carpet if they don't visit that often, but summers, holidays, and one weekend a month is enough that there has to be a balance. He sounds like he barely meets standards when they aren't there. 

Has it occurred to you that maybe the kids miss you because they're sick of having their dad on their backs all the time? 

Youi're thinking of counselling... good. I think you should have started counselling years ago and you may not have ended up in this dreadful situation. However, as we all know, hindsight is always 20/120. I really do think you should go though, even if it's only to say that you truly tried everything. If it helps, it helps, if it doesn't at least you can leave this relationship with a clear conscience.

How long have you been married, btw? How close are you to the magical 10 years (where he could be awarded spousal support)?

OP, can I guess that you went into this as a bit of a caregiver for your DH, willing to help him out in the areas that he struggled - and now you resent him for that?  A lot of us women easily take on caring for men and overfunctioning for them (me included). This guy sounds like he's barely able to function as an adult in most situations - work, his marriage most notably. 

My DH has ADHD (I think, not diagnosed), and he's definitely forgetful and disorganized. I pick up the slack in some areas because of that. But he functions well in his job and is a loving partner who doesn't "forget" to show me how much he cares.

I would suggest you stop paying for his kids to visit - let him get a job and pay for that himself. And that you go to counseling yourself if he won't go with you.  Maybe if you stop enabling his lifestyle, he will want to improve himself in order to keep you and see his kids.  The only kid you are obligated to support is BS4, and if you are thinking of leaving, I'd stop supporting the rest and him, too.

Make it clear that you don't agree with him being a SAHD, and even take the money you use on his kids and put it towards daycare for BS, so when you go to court, you can show that he refused to work, not that you agreed to him staying home. That might help you avoid spousal support.  And if you get majority custody and are the custodial parent, you likely won't owe him child support (depending on your state's laws).  That should be easy to get given his non-functioning as a grown-up.

I agree with your thoughts on ADHD and hyper focus. My SO definitely has undiagnosed ADHD. Once my SO thought he had won me over I was then dropped faster than a piano falling from the sky when he moved on to another burning interest.
 

I couldn't understand why he had changed so much until I met his son who has been diagnosed as having ADHD and I read up on it. Good luck unfortunately I am painfully aware of how bad this all feels. 

Has ADHD and sounds similar to your husband. He has never been on meds but I think should be. I'm pretty sure he has other issues, too, but I also experienced that total change once he "had" me! From that point on, our relationship was filled with lies, bad behavior and devoid of intimacy.

He has older kids that would come visit for several hours each weekend and during that time, he treated me like the hired help. I was supposed to cook for everyone and finance outings but he felt totally fine ignoring me otherwise. The only thing that changed it was his kids deciding they didn't want to have any visitation with him.

ADHD isn't always bad but it needs to be managed by the person with it. My DH also has ADHD and is medicated. He still has some ADHD behaviors, like telling me the most random facts, which I actually love. But the challenging behavior is minimal, either because of the meds or because he's dealt with this for some long that he has coping strategies. And thank heavens, we never had that change once we were married -- he's still the sweet, attentive, loving man he's always been.

You don't deserve to be treated like you don't matter when the kids are there and you know it. It's also not good for your DS to see how you're being treated.