Should I tell a guy [30M] I [26M] don't know personally that his future wife [30F] cheated on him with his best friend [30M]?

Sorry for the convoluted title.

I was good friends with A for a long time. He's around 30 and has recently discovered open relationships and has decided to fuck around with as many girls as possible. No girls are off limits to him, even ones who are ENGAGED.

He told me recently (when he was drunk) that last year at a party he made out and hooked up with a girl who was his best friends fiancee (the bride). They are slated to be married soon. I don't know the groom myself and have never really spoken to him but this sits wrong with me. I have urged A to come clean but to no avail and he denies doing it when I asked him about it when he was sober. He is good at lying and a manipulator.

If I was in the groom's position I would want to know what happened but I have had people tell me to mind my own business and that karma will get A / the bride.

I was thinking about texting the groom anonymously telling him what happened. I currently work with A at work and don't really want him to know I told on him since I don't want work things to get messy. What should I do?

TL;DR Thinking about anonymously messaging the groom and telling him his future wife cheated on him with my sleazy friend A. But I do not know the groom personally and I am co-workers with A which complicates things. But I feel like he has the right to know...

Submitted June 16, 2019 at 04:59PM by Friendmomisloco http://bit.ly/2Il93ZF