<human>: I am fully aware of the fact that this makes me an idiot. She and I talked about it briefly, but she had to go to work. 

So my first ex contacted me a few days ago, just a "Hey, I understand if you don't want to talk, but..." type thing. I texted back, and I shouldn't have. We talked for a couple of days, and I sort-of got back into the way we had used to talk. We flirted some, and I talked to her a little about sex and the like. and I didn't tell my fiancee because I was afraid I'd hurt her. She went to text my best man for me, saw the conversation, and was really hurt, and entirely justifiably so. No screaming, no hysterics, nothing like that. But I hurt her. I made her cry because I flirted with my ex, who I don't even WANT. I don't know what I can do to fix it, and I'm SO scared I'm going to lose her. I promised her that she and I would no longer speak, and sent the ex a message that very clearly spelled that out.

Can you condense the text into three sentences or less?
<bot>: flirted with my ex like a moron. How do I show my fiancee I love her more than I have ever felt anything about the ex?