Posted this in another sub, but getting a lot of hate. Another user PM'd me and referred me here and said this sub deals with issues exactly like mine and the population is largely men who would be able to relate better. I read the rules, seems like an interesting sub. Wanted to get your thoughts.

Here's my other thread: https://www.reddit.com/r/relationship_advice/comments/8861f2/recently_found_out_my_25m_fiance_26f_has_had_an/

I've been with my fiance for right about 2.5 years. We recently became engaged this year, and the only way the timing could have been worse would have been our wedding night...

I was with my best friend the other night at a nice bar and there he ran into someone he knew from work. We hung out with the guy for a bit, making small talk and I guess at some point in the evening he saw my lock screen photo of my favorite engagement photo with my fiance. I ran into some people I knew later on and split off my friend for a bit, and apparently this is where shit gets real.

My friend hung back with the guy from his work, and the guy had mentioned he knew my fiance, but didn't want to say anything in front of me out of courtesy. Apparently he is one of many who have slept with my fiance, and apparently she had a bit of a reputation before we got together that I was oblivious to the entire time. According to my friend, that guy and two of his friends have slept with my fiance, but the guy knew other stories as well. My best friend being a fucking bro and knowing I wouldn't take this well asked him some questions to verify if what the guy was saying lined up with where my fiance went to school/what neighborhood she lived in at the time/mutual friends etc... The guy even texted another friend of his asking him what would be one word to describe my fiance and the reply was "horny lmao".

I've known my best friend since we were very young kids, and we've done nothing but have each other's backs so I know he's not lying. When he told me and certain elements of what he told me fell into place I felt sick to my stomach. Bad thoughts flashed into my head. I don't know my fiance's number and she doesn't know mine, but that's because she refused to answer it a long time ago when it came up. That should have been a red flag in retrospect. We have sex, it's not like a dead bedroom or anything, but she's always struck me as being more on the average if not slightly conservative side of libido and openness. This is mind blowing to me.

She doesn't know I know, but this is extremely hard to keep to myself. When I saw her again I just acted like I wasn't feeling great and went to bed. I don't know what to do guys! This has completely changed my perception of her. I'm legitimately grossed out by the thought of having sex with her, and I've even had thoughts of calling off the engagement. But how tf do I tell her it's because of her past? How do I tell other people why it was called off? Is that even a legitimate reason?

Any input is appreciated!

TL;DR Found out fiance slept with a ton of guys before we got together. Have lost almost all of my attraction towards her and now considering ending the engagement