Maybe I don't belong here, as I'm not yet married to my boyfriend of over a year so technically NOT a "step parent" but here goes.

I've been with my boyfriend for over a year, and we live together. I have a 5 year old son from a previous relationship, and he has a 12 year old daughter. We love them both as if we made them together, and that'll never change.

His ex wife, his daughter's bio mother, is (and I'm sorry ) a PIECE OF S**T. She has been from day one, and it hasn't changed. She has no parental rights whatsoever, he's always had full custody and she's never even had court given visitations rights. By only his kindness does she even have the 2 supervised hours a week and she has NEVER taken him up on it.

A year ago, when we first got together, she and her son (who's only a year or two younger than his daughter) tried to move down where we live and made all of our lives a living hell. She verbally and mentally abused Allyson (the twelve year old) and even physically abused her son who is Autistic and has a myriad of other issues. It turns out, the only reason she came down here was to try and basically sell custody of her son to him because her mother didn't want the burden of raising him anymore and she is a psycho, and to try and win Alex back (too bad lady). When she left after that month of an unsuccessful attempts, Allyson was left HEARTBROKEN. One of the first couple of nights in our new apartment she bawled and screamed about how much she wanted her mother, and how unfair it was. She makes it very clear she loves me, and is even pestering me for another sibling lol and anytime her father has tried to sort of "trick her" when they're alone by saying stuff like " Let's just take what we have now, and just go back to Florida. " she'll ask "What about mommy/Ashley (she switches it up sometimes) and he'll say " Nope, we'll just leave her here" She will get legitimately angry at him.

All of this said, she asked me to legally adopt her when she heard a conversation I had about my step father and how I would have been the happiest kid alive if he'd made me legally his before he and my mother divorced. I'm not sure how I feel about that? I love Ally, just as much as I love my son, and she is JUST LIKE ME (the habits she's picked up over this year we've been a family ! lol) but ! I also she desperately wants a mother since she's never even had a mother figure (he never went "mommy shopping" as he calls it and never really brought anyone into her life) so I don't want to take away from what COULD be a productive mother/daughter relationship with her mother IF the woman ever gets her shit together. When we get married, he already plans to adopt my son and I'm okay with that (as his father isn't even on the birth certificate) and I don't know. I want to, and I want to make her happy, but I also feel that she's young and may not know exactly what she's asking. My initial response was "When you're a little older, your father and I are married,and know me , if you still feel that way and want that, I will happily do it. But I don't need a piece of paper to tell me you're my beautiful and amazing little girl. " What should I do? Listen to my heart and make it legal when we marry, or keep the avenue open for her to have a relationship with her bio mother?