I'm just tired of this relationship

My boyfriend and I are long distance and so we tend to do stuff on Skype sometimes. Lately I haven't wanted to do anything so he thinks it's okay to treat me like shit, but the thing is he did it anyway even when I was. He also uses the excuse that he's stressed. He just makes me feel terrible and I can't leave because he threatens to hurt himself. Also last night I told him I'd be happier without him and that I'd feel better about myself, but I couldn't follow through and actually leave. I just love him a lot and I know he can treat me better because he has through a lot of our relationship (we've been together for 2 and a half years). He only started acting like this after I went through a bad point and would just be mad all the time. After I got better, he got worse