Welcome, I hope you find this to be a good place to vent, contribute, and to pick up some useful perspectives from others who are living the adventure of the blended family dream.

First, it is time for a big no and a foot up G-maw's and G-paw's asses. The second they tell a kid to not listen to a SParent, those GPs are gone, gone, gone.  We had our version of this to deal with from my SS's SpermClan GPs. SpermGrandHag was our particular cross to bear.  "He's not your real dad." "You can't call him dad.", etc...  We did not tolerate that crap and brought escalating abject misery to bear on the toxic blended family opposition.

Like is the case for  you, I entered the kids life when he was young. His mom and I met when SS-32 was 15mos old and we married the week before he turned 2yo.  The Spermidiot has never been involved beyond at a peripheral level.  SpermGrandHag took the COd visitation time.

Time to have a come to Jesus discussion with your SO that the toxic spawn stops the behavioral crap immediately or you will deal with it and neither the little boy nor daddy will like it. Tell your SO to get and keep the GPs firmly in their place or you will deal with them as well.

As SParents, we are equity life partners to our mate.  That makes those partners equity parents to any spawn in the relationship regardless of kid biology.  

If you do not immediately establish the standards of behavior and standards of performance for this kid in your home , life, relationship, and family, this will do nothing but get worse over time.

You have one challenge that I never had to counter. You will forever be confronted by the myth of the Sainted deceased first wife/mommy.  The GP's manipulative toxicity and PASing of this little boy is a clear demonstration of the deification of the deceased mom.

The good news is that the SKid is young.  If you immediately establish and enforce the boundaries required to maintain the standards of behavior and standards of performance you require of all in the blended family environment this SKid may just have a chance of overcoming the current behavioral crap he is pulling.

My bride and I are extremely proud of the man of character and standing in his life, profession, and community that we raised together.  He asked me to adopt him when he was 22. We made that happen.  If you and your SO have a strong equity life partnership and clear collaboration in parenting, things can work out fine. That your SS is so young is one of the critical success factors in attaining that outcome.

Make it clear to your SO that he gets the kid and the GPs under control or you will.

All IMHO of course.

Take care of you.

You're new to the relationship and the boys is only 3 so there's probably time to right this situation.  The key is your partner.  He's not parenting his boy properly if he's letting him abuse your dogs and disrespect you, not to mention drawing boundaries with the grandparents.

I'm guessing he's saddened by the death of the boy's mom and reluctant to be "too hard" on him.  The truth is, he's not doing the boy any favors by allowing this behavior, it will alienate friends, other adults, teachers and everyone else.

It's not fair to you, either.  He's allowing abuse of your dogs and disrespect to you.  This is HIS problem, stepparents, like the position you're in, are resented if they try to discipline.

I'd have a serious talk with him.  Don't accuse or criticize, just the facts.  Since bio parents are so sensitive about perceived criticism, I'd phrase it as your concern.  "I'm so worried about Noah, he's such a (favorable trait) boy. I worry that if he abused other dogs, one might snap at him.". See how your partner responds then you can go into the other issues.

I'm 80 so I've forgotten what appropriate discipline for a 3yo is but others will know.  Obviously, the verbal corrections are ineffective.  Good luck.

P.S. I was that child when my widowed mom brought my stepdad into the picture.  I think part of it was jealousy, someone else taking her attention.  It would have been the same with any new person.

It is up to you to protect your dogs. They may be tolerating the abuse now, but one bite is all it will take to turn this situation tragic. Are you living together? If not, then you need to visit him at his house. If you are, then you need to separate the dogs and the kid at all times. If you can't keep them apart, then either you and the dogs need to move, or the dogs need to be rehomed. This situation isn't fair to the dogs or the kid.
Please look at this situation with your eyes wide open. Your partner is not parenting his child and it is only going to get worse unless he starts doing so now.

Welcome, Plantlady!

You're wise to take things slow -- and to protect your dogs. As a fellow dog mom, I know how important that is. I used to be a newspaper writer and did a big story on kids and pets. So many people fail to properly train and supervise their kids and the results can be tragic.

With the GP, the key is boundaries, as others have said. But it's up to your SO to set/enforce them. What you can do is decide what you can and will put up with and what you're willing to do should those lines get crossed.

Pity parenting is never a good idea and never goes anywhere good.

Keep watching and thinking -- and posting. If your SO can set good boundaries, things could get a lot better. If he can't, you're looking at years of trouble.

Welcome, Plantlady!

You're wise to take things slow -- and to protect your dogs. As a fellow dog mom, I know how important that is. I used to be a newspaper writer and did a big story on kids and pets. So many people fail to properly train and supervise their kids and the results can be tragic.

With the GP, the key is boundaries, as others have said. But it's up to your SO to set/enforce them. What you can do is decide what you can and will put up with and what you're willing to do should those lines get crossed.

Pity parenting is never a good idea and never goes anywhere good.

Keep watching and thinking -- and posting. If your SO can set good boundaries, things could get a lot better. If he can't, you're looking at years of trouble.

You can look up my posts and blogs for a detailed story, but the Saint Martyr turned out to be an entitled leech, that leeched from the tax payer money all her life, then quickly monkey branched to my SO, and squeezed two kids out just before she carked it (knowingly) as a way of guaranteeing her immortality I suppose. And even the few years that she was in their lives, she was very uninvolved mother. She needed her sleep, so SO was quickly dispatched to the spare bedroom with the kids to do all the night feeding, sleep routines etc., while also getting up early to go to his corporate job. 
Fortunately for me, the grands seem to like me, but I don't like them, and can see where the mother got her attitude from: they're still sponging off the state, do absolutely nothing  with their days, and still like to flex their power, refusing to take the kids for a am occasional weekend, take forever to respond when they do agree to take them, create some other obstacles, making SO drive for an extra hour there and back when we're coming back from an already long trip just to pick them up (my SO has their road toll tag permanently linked to his credit card and also pays for their petrol when they come). 
 
The kids are disturbed, obnoxious candidates for juvenile justice system in the making. Thankfully, they've never dared to be that way to me, but nevertheless, it's awful to watch them being that way to each other and their father. 

Both are tweens/teens, and it's becoming quite obvious they got an orphan pass throughout their lives (mother died when they were toddlers/kindergarteners). The other day they had a fight about some stupid toy, and next thing we know, one of their new friends' parents texting, saying that he came over crying about his mother. Luckily, my SO knows better and said it was about the toy. But what transpired was that parents automatically assume that any upset must be about the mother, especially any new adults that encounter them, as to them that's the fact that stands out the most. Once they suggest that, the steppos go along with it, because that what gets them the most attention/treats/leeway. 
 

I've asked my SO to stop whitewashing the BM's image, since he's not doing himself any favours either. In their minds, they're hard done by, because they have to stay with the mean dad (who's the only one who'd ever done any kind of parenting), whereas their mom would have been this saintly, forever patient creature, allowing them to do whatever they want. I also feel that any anger they may have about BM abandoning them (not that she chose to die, but that's how kids' brains work), is channeled towards the father, because he's the available target, the parent who stayed. 
 

What worked for me was hard boundaries. Like you, I decided to keep my own place (and it's lovely - I've spent a lot of time decorating and gardening) while they're smashing up their fathers house. My SO sold his old house and moved minutes away from me, which makes things a lot easier. I no longer go on holidays with them (SO and I go on ours, and he takes them separately), nor they're welcome to any local restaurants or wineries with us because of a physical fight and ear piercing screaming they caused each and every time. 
 

Both now have mental heath diagnoses and medicated - nothing surprising here, following mother's lineage. Aside from providing guidance about assessment and treatment, I take no part in their mental health needs. That's on SO. He married into disease and dysfunction, and that's his cross to bear, not mine. 
 

In short, keeping them as separate from me as possible works best for all of us. When SO comes to my house, he gets a break from constant aggression, violence, oppositional behaviours and nasty bagged, frozen foods (which is all they eat). 
I support your decision to implement boundaries, and perhaps at some point you'll have to tell your SO that all contact with the grandparents should be supervised by him and not include sleepovers.

IMHO.. I think you need to seriously consider what this will mean for the next 15 plus years. 

Interfering Ex inlaws that lost their daughter.

BF that is pretty happy to give up the responsiblity of his child .. probably to get a break from it.. to those people... who will be a constant presence and reminder of his EX in your home and life.

BF that has not stepped up to parent.  Why are YOU the one having to remind, cajole and plead with a 3 yo...????? Why is his father sitting there idly while the kid repeatedly does things he has been told not to?

If the boy is 3... I can't imagine that you have been in this relationship but for so long.. you don't live together.. and finally "LOVE" is not enough.. if you stay in this relationship the drama, enmeshment and stress are going to be a regular part of your life.

It's NOT the fault of a 3 yo.. seriously.. this is in no way HIS fault.. it is the failure of all the adults around him... and they are unlikely to change..

I would chalk it up to wrong situation... nice enough person.. but undatable.

This 3 yo without a BM this kid will be with you 24/7/365--...for another  16 years I'd he is not jailed first., you must understand this, there isnt no way to avoid that. .  It's very unfortunate that this family was devastated with the lost of the BM and I feel for this kid. Saying that

Your BF must parent his kid, what he's doing a poor job now.  You must have a talk with your BF . Because how do you live with someone and disengage from the son ? Do you really want to live like that?
 BF must lay down the law to his DS and get him to behave properly.   SS needs help. Professional help with the lost of his BM.

You must understand this and set up a time line. As what improvements are needed and by when. You don't need total improvement, but 25 % in two months. 50% in 6 months.   And decide if this is the man/family for you. Or cut your loses and move on.

best of luck 

I think it's wise that you are taking things slow. I'm doing the same, but in my case the youngest skid is 15. Plus, i am divorced with kids of my own who live away at college so i don't feel like i'm wasting my childbearing years (idk if you want kids of your own.) 

This kid is 3. And his dad is not handling him properly. You have stepped back, which is totally understandable. But - that means NOBODY is raising this child properly. He's going to grow up and his behavior will get worse. If your plan (as mine is) is to wait for things to become "livable" with your SO, that's a minimum 15 years, and that's for kids who are parented well. Coddled kids mostly don't launch on time. 

And yet another welcome and “Good for you” from this dedicated dog-lady. Our ‘girl’ was in her 17th year when she crossed the Rainbow Bridge and had become a tad grumpy in her dotage. When a friend’s granddaughter continued to poke and tease her, after being warned, and our finally removing the dog, the child (unseen by Grandma) pursued doggie into our bedroom. 

We heard a growl, then screams and although our dog’s nip did not break the child’s skin, she was hysterical and Grandma was furious.

Our home, our beloved dog, lots of warnings and removal of the pet, yet it was the ‘nip’ that destroyed a friendship. Quite frankly, I was delighted to have the undisciplined youngster removed from my acquaintance. There are probably some moms on the site who think I’m awful but our ‘girl’ was far more important than anyone’s ill-behaved grandchild. 

Hon, your ‘girls’ were there first! They do not deserve to be tormented by a child who refuses to obey reasonable instructions. It’s a shame to see a young child provoking dislike because of inadequate parenting. I agree with Rags, that the boy’s grandparents’ influence on the lad is harmful, particularly since, they tell him he doesn't have to listen since I'm not his mother.

You are wise, indeed, to keep the brakes on your relationship with your boyfriend; too many red flags waving! Quite possibly, he's not yet ready to take on a new partner.

To a year from now.   He will still treat his kids as adult confidants and mini spouses, then get aggravated with you for suggesting changes and actually parenting them.

Flush him now!  A leopard does not change its spots.  On this forum if you are here it's already a problem and the success rate is probably less than 0009%