My question is in the details, please someone help me! Thanks, I appreciate it!!?

Hi!! I have a big problem!! Me and my man discussed a few months ago that we were gonna get our own place together so that me and him can start fresh when the baby gets here(Im pregnant)! Now, as he said he needs to talk to me! We talked yesterday, now he changes his mind and thinks that we should move in with his mom once she gets this house!! He said we will have our own room and we will still have our privacy! I am not happen with what he wants to do at all!! For one, I am not feeling that we are gonna be living with another parent when we are trying to be parents of our own!! I figuired it will be the adult and right thing to do if we get our own spot!! I thought it was finacial issues casue I was kinda struggling with money but its more than that!! He figures we should stay with his mom because rent will be even higher in about 3 years adn we should save money by staying with his mom nontheless he wants to take care of his mom becasue thats the only parent he has and her body is all messed up and he doesnt want nothing to happen to her!! Thats a bunch of crap to me because the women is only 41 or 42, which is not old at all, am I right? My mom is 50 and my dad is 53QQ My dads body is messed more than his mom but he doesnt expect me to take care of him!! What is up with that? Am I missing something? I dont want to live with his mom because as adults, we have to except the fact that live will be high and hard if you dont have a lawyer type job or something!! Nothing is cheap!! Whether we stayed with his mom at a house or not, feel me? So, what should I do becasue my man would rather spend 22,000 or ;ess on a nother car than living, can somene please help a sista out!! I am so lost, I dont know which way to go or what to do! Help??????