Idk what to do anymore...

So I’ve been with my fiancé for 3 1/2 years. Everything’s is great except for one thing. His mom is starting to become a problem in our relationship. He moved out of her house 2 years ago and moved into a studio apartment with me. He’s always been a mommy’s boy and I totally respect that and I am thankful he has a close relationship with his mother. However this is becoming an issue in our relationship. She’s always making him feel terrible and guilt trips him because he barely sees her. She lives 2 hours away from us. He works full time and often does overtime hours. I myself barely see him. Only in the afternoon and that’s if he comes out early. He tries to see her as much as he can but it can get complicated at times. She sends him care packages to our home. She calls and texts him at all times. And now she’s even trynna make him feel bad about being so far away from her and is trying to convince him to move back home or get an apartment near her. She also tries to have a say in everything we do. He does not see a problem with this it all. I try to communicate with him about this but he just thinks I’m just trying to come between him and his mother. And that is not true. I would never do that. To me it seems like she isn’t ok that he left the nest. He is a 23 year old man. Idk how she’s gonna act when we have kids of our own and are married. I need advice ladies.