How do you deal with a mama's boy boyfriend?

There's nothing wrong with being a mama's boy! in fact it's even admirable; it means he understands a woman's perspective on a deeper level. So long as he is able to function like a mature adult without his mother by his side, then it's perfectly fine.

Just be honest and talk to him regarding your specific concern. That way he knows what you feel and both of you can come up with a solution.