I've never been in a relationship with someone that has a child

we’ve been together for a year now. and they’re are things that concern me but i’m not sure if it’s even my place . i know that the baby comes first no matter what that is no issue . my issue is that he never talks to his ex when he’s around me he’ll go outside.. when he goes to visit the baby i do not go he’ll stay for the weekend and the babymomma says that she’s not comfortable leaving the baby in the dads or grandmas care so she has to spend the whole time there and stay the night all that .. and i don’t know any of his family he knows all of mine he knows my friends i post him on social media all that which is normal. and he does none of that . how can i sit him down and talk start the conversation.i need help i really love this man and i’m tryna fix whatever’s wrong . basically i need advice idk what is ok and what’s not ok or too soon