Family

My baby father always tell me he wants his family back but he has a fiancé he takes me out but I can’t even capture moments with him simply fact because he’s in a relationship I want things to work between us but that’s just too big of a commitment he has made with the other female should I hang on or let go? We share kids they share nothing and as bad as I want this to work out I feel like he will never leave her to be with me again. They play house with MY baby, picturing themselves as a family with MY KID .. idk how to feel about this