Roommate issues

okay so everyone knows that everyone has sex, and i completely understand that it just happens, but i just get so uncomfortable hearing my roommate and her boyfriend going at it. the music was louder than the last time which is fine, but it bugs me. i don't know... i wouldn't just have my guy over, all the time for that matter. she doesn't even give me a heads up so i can leave or something. what should i do? i've already talked to her about him being here all the time, and if i have to again, i'm going to be a bitch about it.