[MFM] GF cheats and begs me to take her back.She breaks up with me a couple months later. I move into the guest bedroom, and she starts bringing her new guy around.

Sorry for the length in advance. I just don’t know what to do. I feel so conflicted.

TLDR: GF cheats on me and begs me to take her back. I do, but then breaks up with me a couple months later. Our lease doesn’t end for another 3 months, and decide that I should move into the guest bedroom for the remainder of our lease. She starts dating another guy while we are still living together. Find out it’s the guy she cheated on me with. Feel so conflicted.

My ex GF and I met our senior year of college, and dated for 5 years. I had always had cuckold and humiliation fantasies, but I never told her about them because I knew she would be turned off by them. We moved in together about 2 years ago, and things were going great (or so I thought). We were talking about getting engaged within the next 12 months.