Left After Seeing Best Friend Call

AITA for leaving after finding out who my boyfriend cheated with? I’m 26,

and I ended a three-year relationship in one night. I found out my boyfriend, Mark,

was cheating on me — not with a coworker, not with an ex — but with someone

I trusted. I didn’t even suspect anything until his phone rang while he was in the shower.

The name on the screen made my stomach drop. It was my best friend. I didn’t answer

it. I just waited. When he came back and saw the missed call,

his face changed instantly. No confusion. No denial. Just panic.

That’s when I knew it wasn’t a misunderstanding. I packed a bag and left without saying a word.