I would seriously think about finding a new BF. JMO of course. I have dated a momma's boy and I am SOOOO glad we parted and went our separate ways. He is now 37 years old and is STILL a momma's boy.
Your BF should have stuck up for you IMO. There was absolutely NO reason for his mother to treat you that way! She may change in time but I would not change who you are just to please her. Her son fell for you because of who you are. If she doesn't like it then tough S@&#!!!! Be careful and look out for yourself.