Boyfriend's family is way too prudish

I can't even deal with my boyfriend's family anymore. They're extreme christians and I am an atheist, so is my boyfriend, but they still think we're all christians. We (me, boyfriend, boyfriend's older brother) were watching an episode of It's Always Sunny in Philadelphia and the characters went to a strip club and my boyfriend made a comment about all the glitter. Backstory: he despises glitter and he will flip out if he even sees a piece of it somewhere. I made a comment like "how did you survive going to a strip club if you hate glitter so much?" No one responded at all and we continued watching. My boyfriend sent me a nasty text saying "my brother didn't know I've been to a strip club so thanks a lot" etc. I got thrown under the bus for a mistake HE made when he was like 18. We're both 20 and we've been dating for 9 months. Recently, he moved out of our apartment and moved back home until we find a new apartment. Since then, none of his family will leave us alone for 3 seconds. His brother will stay up and chaperone us the entire time we're here. If we go upstairs for 5 minutes, he comes up to check on us. They have no reason not to trust us and it's really pissing me off. We're adults, I think we can be trusted to not fuck each other if we're alone together for 5 seconds. They freak out if I even walk into my boyfriend's bedroom to get a phone charger, even if my boyfriend is SITTING ON THE COUCH WITH THEM. I can't stand them anymore. They're very against premarital sex and his brother is especially obnoxious about it. He acts like he's in charge of both of us. I just can't deal with it. I feel like our whole relationship is a lie.