On and off relationships

I just got out of an on and off relationship of ten years. I'm 26 years old and very frustrated. Every time we break up, 2 or 3 months pass by and he comes back. Of course, I go back. It is very unhealthy for me because it makes me feel worthless. I know I am not ugly, I can actually say I'm attractive. I say this because there are lot of guys interested but I can't seem to move on. That does not help my self-esteem though. When I am not with him, I tend to get very depressed and you might say suicidal. All I wasn't to do is sleep so I won't have to think about it. I take sleeping pills so I won't have to feel this pain I'm going through. There's been times that I've taken so many pills that I can't feel my body anymore. How can I get over this, I've tried going to a therapist but it did not help me at all