I think I’m a cuck, I don’t know how to feel [Cheating]

So me and my fiancé had just gotten new phones, she got hers that day and mine had to ship. I told her I’d take both of our old ones in on a trade in once I got mine. Well while I still had her old one I got on it and got on her snap out of curiosity. I am deeply regretting it now.

She snaps a lot of people, it’s just how she’s always been but I’ve noticed she had been messaging a guy from work a lot more than the others so I slid to read their chat. I can’t unsee what I saw in there.

My innocent fiancé was constantly flirting with this man, talking how she’d suck the cum out of his dick and she likes it messy dripping out of her mouth (she barely ever sucks my dick and hasn’t ever swallowed my cum). Sending him a pic before she’d send the same one to me. I immediately got full of rage, jealousy, and lust. It turned me on and I feel horrible about it. Idk if I should leave it be and move on or confront her about it.