In a lot of ways, right now, what YOU feel he should do is irrelevant. He's doing what HE needs to do. And honestly, that 4 year old sees him as a father figure at this point, sounds like that's all she's known. It would be cruel to tell her "sorry honey, I can't be your daddy any more because my girlfriend doesn't think I should".

I seldom recommend this, but I'd say break up and go find a guy without kids. You're not married, no kids together, you don't like this situation and I can PROMISE you it will only get worse as they get older - why do that to yourself? Go find a nice guy with no kids, you'll be happier for it.

When my DH married his psychotic now-ex, she had a 2 year old daughter. Her father has ever been, part of her life. She sees my DH as her father and calls him Dad. He isn't her biodad, but he raised her and considers her his daughter.

I will probably be the unpopular opinion on this one but I was in a situation that was similar. FDH's ex (BM2) had a child from a previous relationship and this childs dad was never in her life so she viewed FDH as Dad. However, he allowed BM2 to convince the child that FDH IS her BIOLOGICAL Dad (they are different races I felt that this happening was cruel to the child). Anyway thouhg after we got serious BM2 didn't want her child to be around me so she was trying to break us up using a child that was not biologically his. She wanted him to take her child when he'd take their child together for custody time but she said that I couldn't be around. Eventually he told her this was her choice and that he wouldn't be taking her child anymore. He eventually explained to the child that she wasn't his but he'd always be there if she needed him. He took a lot of slack from everyone in her family for this but I was happy. Of course I didn't want the child to be harmed emotionally but I wanted nothing to do with helping raise this womans child a woman who has made my life a living hell and still continues to do so after years. I was very relieved that she is no longer a part of his life. Apparently she's moved on and has adjusted fine. I mean we are a group of people that have step parenting, blended family issues and I couldn't imagine blending my family, his family, his kids from his ex wife and his kid from his ex girlfriend and this other random kid. It's hard enough as it is without mixing someone who isn't even a biological child. I have trouble bonding with my YSD let alone her sister from another mister.

Look, what it comes down to is this - your BF wants those 2 girls with him. Full stop. DNA doesn't matter, deadbeat mom doesn't matter, stress doesn't matter, whatever else you're throwing out there, just recognize that it doesn't matter. This is what he wants. Now the question becomes, can you accept it? Because it's not going to change, and if their mom already gives them to him for "months" then chances are he's going to end up with full custody eventually. Are you ready for having them 24/7? Forever? If not, get out now.

I agree that thinking about asking him to stop parenting the olderer one is inappropriate. I also know that children should be told in age appropriate language as soon as they can understand what their real relationship with adults is. Adopted for instance or whatever.

Are you so desperate to be seen in public with a guy walking by your side that you'll put up with this for 20 some years?

Oh and longer because even high school graduated kids don't really go away. The ex-wife for two decades and the kids for the REST of your life. Oh boy, fun.

Come on girl there must be a million guys out there without children. Go and find one. Tell your soon-to-be ex-boyfriend that when he asks a girl out in the future first find out if she has children so they at least can be of help to each other.

Have you considered that his primary (but maybe subconscious) motivation may be the need for sex and someone to help with the kids? Unfortunately for you this is the underlying reasons many men to find a second partner quickly.

Don't walk - RUN.

Just read your own words... you resent them.
And I'd really question if he's "putting up with them" sounds more like he's parenting them. He's stepped up, into what he sees as a void. That's what a father does, whether DNA shows a link or not.
And parenting is stressful, steps, bios, foster kids, whatever. End of story
Like so many have said, I think you need to walk before any more hurt occurs, you, him, or the children.
It's probably best for all concerned.
You'd like their mum to be more active in their lives, but if she was and he were still involved as their father I suspect that would cause you resentment as well.
Not everyone is cut out for this, hell, even the easiest and most smoothly blended families bring moments that make step parents think it's time to go... Or so I've heard...our blend is not that smooth
I think the most loving thing you can do right now is admit this is not for you.

You think he is still in love with BM because he wants to take care of his children? If mom is a deadbeat, he should step up. Even if she wasn't a deadbeat, it sounds like he loves his kids and wants to be there for them.

At 2 and 4, they need a stable parent. It's not like they are on the verge of adulthood and can just fly out on their own.

I understand the resentment and don't judge you for it. What matters is how you handle it. Walking away is okay (although very hard, I know). It's better than expecting him to not be there for his kids. It doesn't sound like mom is going to magically become mother-of-the-year so....

It's not the kids' fault that their mom is a deadbeat, nor that the 4 year old is not biologically his. He loves her like she's his, that's all that matters.

It does sound like he could use some structure and discipline in his parenting of them. Maybe you could turn him towards some parenting classes or info on the internet or something.

You are an outsider and always will be to a guy like this and that will get worse as his kids pick it up more and more. Nobody doubts your love for him and nobody doubts you have lots of wishes. So what? You're not going to love or wish his kids or his priorities away.

Listen I know its tough to start over, sort through all those toads, but get out and ask every guy you meet "Got Kids". If the answer is yes then move on just like all the other smart childless women of your generation.

You're hearing it here over and over and just don't want to accept it. This will not solve itself and nothing you do will make it better. Bite a bullet, tell him you made a mistake, close your heart to his pleadings and for once do what is right for you.