Lack of sex

My boyfriend and I live together and are pretty much around each other often. He's very affectionate but we literally only have sex 3x a month. Like this isn't normal to me. Like he turns it down, bjs, everything until he wants it. I've asked him about it but he always turns it into a conversation about something else or avoiding it all together. It hasn't even been a yr of us being together. He constantly talks about marraige and us being together but I can only imagine how worse it could get 😔😔 help!!