How to deal with my boyfriend and his two-faced family!?

Okay, so i have been with my bf for almost 3 years and we are bout to be in 11th grade. He can be sweet when he wants to but...he can get really mean sometimes... but i love him and he loves me even if he doesn't show it all the time. well his parents are really rich and think they are all cool and nice because they take us out places all the time... [but they never leave us alone and the mom always has freak attacks that i'm taking her little boy away or w.e] but anyways they are very religious and feel like everything they do is right when really they are plain sneaky and mean! but they do mean things and they are two faced with me. like one time the mom asked me if i was gaining weight then right after she asked if i thought she looked thinner?! and my bf didn't stand up for me. and normally if i have plans and they randomly call and say hey we are all going out to have fun wanna come? i always say YES! ill do anything to see my bf even if i have to put up with is family. and i have lost friends over this people....i have like 1 friend i hangout with now. but today after drivers ed with my bf he was waiting for his parents to pick him up and i was waiting for my bff [my life only real friend] and his family got there first and they were like hey wanna come we are going out! and i actually said well my friend is already on her way..i really wanna come but i don't wanna stand her up because she is doing me a favor by getting me! and they said oh no problem!!! all nice and everything! then.. after my friend got me my boyfriend called and said yeah...we all had a talk my family was like wheres the girl we know? the girl that would drop everything to come with us! and they said she better not be cheating on you! and fyi i don't talk to boys....my bf doesn't let me =[ even tho i would never ever cheat on him im crazy about him and i have no desire to be with another guy. but yeah in the end my bf said no one went because i didn't come... and there are a lot of other things that have happened but here is what just happened. i need help. my sister says i will never win with these people. they are manipulating and my bf takes after that... help