My boyfriends mom is killing me

She has always had an issue with me after my bf and i broke up in hs and got back together. She has said rude comments, given me eye rolls and always tries to correct me on everything. While now she has taken it to a new level. My bf and i are long distance and only see each other 1 weekend a month. Its this weekend my bf has to go to and open house tomorrow to look at an apartment which is near his school. He doesnt have class monday and offered to take me to the aipprt since its on the way. Well has mom is bossing him saying if he goes to look (he has to cause its one of the few in his price range and its very nice) she wants him to stay there and for me to find another ride. He was supposed to come to my family dinner tomorrow and his mom said if i want to see him i can drive an hour to. Well i'm home to also see my family soi don't have the timeto that when his house is 20 minutes away. He is 20 and very responsible. My bf is upset cause he left my house at 6 tonight cause his mom wanted him home for dinner. I understand she wants to see him but he is home every weekend. She is coming between as much as i try to ignore it. I want my bf to do what he thinks is right if said he couldnt drive me i understand but i don't want him to do what his mom says because she always chooses everything against me. Please help i love my bf and want to be there to support him but its so hard. I am a very strong family person and his dad loves me. I understand its her oldest son but shes pushing him away and making it hard for me to date him which is probably her goal cause her she him to date a different girl and is very vocal to me about this.