When is it time to slam the door on one mess of a relationship?

I'm in a relationship with a man, I'm 25, he's 24, we are both in school and living together. I'm a grad student and he is finishing his undergrad degree (finally). We've been together for almost two years now. My dilemma is deeper than the two of us; our problem is with his parents/family. He was raised in a very paternalistic household where the woman keeps quiet and the man runs the house (and his mouth). In my opinion, his family life is a disaster and it has negatively impacted him as a man and boyfriend. He acknowledges all of this information as the truth and is evenly attending therapy and reading books about the subject. I, on the other hand, was raised in a maternalistic environment where the man retained his position of authority as Dad but Mom was outspoken and essentially "ran the show". I have become that woman. I can be very meticulous and specific with my wants and needs. My boyfriend and I have been butting heads for so long; we fight and argue all of the time about the same stuff. It's a struggle for control between the two of us and I'm beginning to think that no couples therapy or book is going to help revive our relationship. I almost just want to pack a bag in the middle of the night, leave a note, and disappear from him forever. Just recently, and one reason why I'm writing and seeking input, is when we were at his parents home for New Years morning and the night before we apparently were fighting the entire car ride home (his mom picked us up from the hall). I've lost all patience for arguing with him so I demanded to let me out and find my own way home. That didn't happen. When we got back to the house we fought a bit more and then I tired out and fell asleep on the couch. In the a.m. I asked him to please get ready to go, I was still very annoyed and upset and extremely hungover and sick. But this goes beyond having drank the night before. These problems are social and private. They never have been resolved. To get to the point, we started to argue again, apparently the reason was because I was dancing too much with a friend of his while he sat at the table "ignoring" me. I don't recall dancing offensively with anyone. Anyway, his horrible Dad comes downstairs and somehow gets involved in the conversation. He's a loud mouthed man that feels as though he can offend anyone whenever he pleases (i.e. I heard him once say to his wife while she bent over in the kitchen, "move that big ass out of my way" and to his brother-in-law's wife "you are a hot lady with a hot body" after drinking too much at a daytime bbq.) Disgusts me. Anyhow, his Dad went too far with me this time and I didn't keep my mouth shut, in fact, I told him that I wouldn't dream of bringing children around an in-law like him and that I think he is ignorant and rude and lacks respect for his family and society as a whole. He did not like that one bit! I don't believe any woman has ever talked to him that way! After telling me to get the hell out of his house and "I never want you back around here" I pushed more! Damn right. I told him he owes me an apology and then I apologized for how I said what I said but NOT what I meant by it. Then, surprisingly, his wife chimes in and agrees with me, and then my boyfriend did too. That felt nice, but I still was pissed off to hell with the two of them regardless. Here I am, in the house of my boyfriend's parents with no family or support of mine in sight fending for my integrity and strength without anyone's help. I was in the twilight zone and I wanted out! Being that I am a soon-to-be attorney, I was taking the heat very well, but I was emotionally drained and weak. I had to leave. We returned to our apartment without speaking a word to one another and for the past two days it's been very quiet and serene between us. It's almost like we're waiting in the "eye of the storm" and once we make a move the thunder will roll again and this time the damage may be irreprable. I need some advice and guidance from anyone who knows what I'm going through. I'll tell you more details if you'd like to hear.