<human>: I cheated on my ex girlfriend of 2 years in college several times. It was a stupid ass thing to do, we were fighting, constantly at each others throats and neither of us had the balls or relationship experience to know the best thing to do was to break up. I've never cheated on another woman since. I did tell her what happened and that cause a whole other set of drama that ultimately ended with us going our own ways. All in all, we were pretty fucking poisonous for each other.

I met an amazing girl 3 years back and we started dating and I proposed on New Years. My ex messaged on Facebook one day with a very detailed description of everything that went on during the period I cheated on her. Stuff only my ex would know. 

My fiance and I have never talked about our past exes in great detail, just bare minimum, all she knows is that this woman and I ended our relationship in a really bad way that messed me and her up. 

Cheating is a big no no for my fiance. Always has been, always will be. I've explained to her that it was a stupid period in college where I did shitty things in a shitty situation. She says she understands but doesn't feel certain she wants to be married again. The things my ex told her were very detailed and got in her head completely and now I don't even know if I'll be marrying the woman I want to spend my life with.

??????? Need help fixing relationship

Can you give me the gist of the text in a nutshell?
<bot>: cheated on ex in college, ex messages fiance over a decade later to tell her I cheated, now fiance isn't sure she wants to be married