HELP😣😣

what do I do. my boyfriend is the absolute love of my life. but he feels like he needs to leave me to be with his baby momma from 3 years ago. before we dated we were best friends. he currently lives with me and says that if she says she wants to work things out he will still live with me but around my family things stay "normal". I've always been left for the ex and this is completely tearing me apart and I don't know what to do. I can't lose him!