Boyfriend says, “you are going to leave me again.”

I have arguments with my bf. I left him twice and came back. We are not able to rebuild a relationship.

Here is my model:
C : He said, “you are going to leave me alone again”
T : You cheated on me in the first place and you let me go. There is nothing good in this relationship.
F : Guilty. Defensive
A : Aggressive. Back in my suffering in the past that he does not understand or even responsibility for
R : Unable to leave. Unhappy staying in a relationship that does not work. Cry and do nothing for the future.

How can I change my thought?
T : No, I just want to live a life where I have plans for my career, family and for our relationship. But then I’m not satisfied with the F because I feel sad about it.

What thought should I have to have a good feeling that can lead me to action?

Other thought : OK, it is your problem thinking that, not mine, deal with it. I cant tell you if I will leave you or not. F: Defensive

Thank you very much.