I agree with everyone else, you need to take a break. I was in a relationship for almost 4 years, but, we broke up because there were severe issues that could have been avoided if we had taken a break when things started to go out of control.

It's one of the hardest things I had to do, breaking up with the person who I loved more then anything. But, I've learned something in the 6 months after we ended it: You have to put yourself first. No matter what. It's a hard choice to make, but I promise you that if you put yourself first you'll end up a happier person in general.