I have dated him for one year. And have always felt the need to break up with him because of our differences but never could and never said much. So the last three weeks of our relationship I started voicing out.. asking him to spend more time with me as we barely spent time with each other or bonded. he couldn't understand why I asked for this. To distract myself I hung out with other friends. And was always honest about where I went. So this one day I hung out with this guy friend of mine and even told my boyfriend about my plans and he did show some discomfort but told me to go. ... I asked him if he was really ok with it and won't be mad or something later he said no. And I went. After I came back he acted super weird. didn't talk much... And out of nowhere started accusing me of cheating. I defended myself and told him that I was honest about my outing so it wasn't called cheating. But he wouldn't listen. So I after a while of trying to fix things I broke it off... since he wouldn't even communicate about the problem. But it felt really bad to break up with him on some misunderstanding so I still kept trying to talk it out with him but he would ignore. And he started telling people that I cheated on him and that he didn't know about the outing and my guy friend liked me. I felt really hurt about it. I didn't expect this from him. He was friends with me before dating for like three years. and asked me out later... but this behavior broke me. I defended myself wherever I could. But it still bothers me and I can't make sense of why he acted this way... I may have not been happy with him... but I loved him. Also he got involved with a girl 2weeks after our break up. they were friends during our dating period. I do have a theory... I know he has insecurities. also before dating I still had feelings for my ex so I kept rejecting him at the time... and he got very upset about it. I feel the past and his insecurities have somehow clouded his judgement.