Here's what you do...... Break off that engagement before it's too late, YOU should be his first priority not his mom, sister or step daughter.
I am 34 he is 46 I am enagaged don’t think he values me in his life he just want to have kids with me. His priority is his mom and sis (36) and his step daughter 35 and her kids my ; I love him not sure what to do?
You just described one big ol' huge orgie (figuratively speaking) if you stay with him. I hate to be blunt but that is way too many people to put above the woman he supposedly loves. Please DON'T have kids with this mamas boy!