40. Worst Birthday
I was in Japan on my 24th birthday on business from the US. Now, I was feeling pretty good about my career path and was finally letting go of my self-loathing and my insecurities as a person, etc
At the same time, my personal life was in crappier, typical. I was having problems with my then-current bf at home. Turns out that on my actual birthday, he was banging some chick.
When I got back, my roommate hinted at the bf hooking up with a witch at some club. BF completely denied it, looked me straight in the eye, got a little weepy-faced but indignant, etc., when I confronted him.
Only when I pulled a partially used condom wrapper off of his bed did he finally admit to it. Took me years of self-medication/meaningless relationships to get over it.