A Secret That Could Ruin Everything

I (29F) cheated on my fiancé with his best friend (31M), and keeping it secret

is eating me alive. Throwaway because my main account has people who know me.

I know I’m a terrible person. I’m not here for sympathy—maybe just to finally say this

out loud somewhere. I can’t tell anyone in my real life, and the guilt is making me feel like

I’m walking around with a grenade in my chest. My fiancé “Evan” (30M) and I have

been together for 10 years. We’re the couple everyone thinks is endgame—stable,

communicative, goofy, the whole annoying picture. We got engaged last

year and planned a small wedding for next summer. His best friend “Mark” (31M) has