<human>: Can you summarize the given text in a few sentences?

So I broke up with my Ex about 5 months ago. I found out she cheated on me at the very end of our relationship and she is now with that other person. I still talk to her and have feelings for her. On my last vacation home from work (I work overseas) we hooked up a few times. She claims her and the other guy aren't in a relationship but she is pretty much staying at his place and started seeing him (he is actually her old Ex) before I let for the job and before we were broken up. I told her she should tell him but she doesn't want to cause it will " start more sh*t" and " I don't want him mad at me". We got into a fight today on the phone and Facebook today and I ended it by saying if she contacts me again I'm gonna tell him. Part of me thinks I should let it be and move on or patch things up with her. The other half says tell him and let her get hurt like she hurt me. Any advice?
<bot>: Part of me thinks I should let it be and move on or patch things up with her. The other half says tell him and let her get hurt like she hurt me. Any advice?