Almost 30 years olds and his mom runs his life

So there is about a 9 years age gap between me and my bf. Almost 2 weeks ago this sunday,(the Sunday before Christmas) my bf brought his mom with him to Sunday school and she started to attack me bc she was jealous that Brian(my bf) was going to spend Christmas with me. She said she felt second rate when in reality Brian is her little puppy. She has him on a leash when she says jump he says how high.

Lately all I've been hearing from my family is that it's only going to get worse, like she's only going to try to break us up. I love Brian but I'm afraid if i tell him what I feel his mom is doing it will end in a big argument. I'm scared I'm going to lose him, that he'll choose her over me