jealousy

I have a relationship for 7 years with a man. I love him so much but sometimes I doubt with him. When I was doubt with him, I am looking for another man and try to get near around them. Then I figured out that I am only playing. I figured out that I only love my 7 years relation. I did it several time. This man (7 years) know what I did and said can not continue our relationship because what I did to him is hurt him so much. I really want to stop him but I think I hurt him so much. Even if we are together again, I am afraid the problem still remain. So what should I do?