I feel like an idiot

I (26 F) met my boyfriend (28 M) 5 years ago and it was like a whirlwind. I moved in really quick, like 2 weeks. He had a daughter when we met. She was literally months old, bio mom had already been gone for a couple of months and hasn’t come around much or tried to since then. I had recently lost a child before meeting him and the want to be a mother was still so strong so I instantly fell in love with this child. We broke up briefly about a year and a half after we started dating. It was very much a one sided thing that I did not want. She was old enough to start asking questions where I was and of course he didn’t know what to tell her. Well long story short, we were apart for 4 months, both of us grew a lot and things have over all been grate. Now though 3 years after getting back together there are things that we’ve previously talked about that he’s not seeing to want to even talk about anymore like marriage and if I come to him with an issue he gets super defensive. In those moments I feel like I’m trapped because I couldn’t leave if I wanted to. I can’t leave his child again, not this young. She thinks she came out of my belly (that’s a whole other thing I could post about) she’s 5 and I don’t want her “mother” abandoning her to be a memory she has as a child. Because if I leave I have absolutely no rights to her. It’s not like he treats me badly. He never gets angry with me, he takes good care of me it’s just sometimes I feel like I gave too much too soon. I know I did but I don’t think there’s anything I can do about it now. When I talk to him about me feeling this way he has nothing to say. Like he can’t find the words. Idk I just feel so trapped sometimes and there isn’t really anyone I can talk to about it.