I [32M] slept with my ex-girlfriend's brother [23M] and my life is now a nightmare.

Background: I was kind of a weird conundrum in high school and college. I was on the football team, hung out with the jocks, and was just a very typical masculine douchebro. However, I never had sex or even went on a single date until I was 24. I used to lie to all my friends about one night stands from other schools. Looking back I realize how cringey and embarrassing I was.

When I was 24 I met "Anna" through work. I liked her immediately. We started dating, and ended up living together for six years until we were both 30. The relationship was good but not great, but she was my best friend.

During the last year we were together Anna convinced me to see a therapist because I had become kind of depresed. I did therapy for eight months and long story short, finally admitted to myself that I'm gay. I spent a lot of time hating myself once I realized this and sort of took it out on Anna. I wasn't horrible to her, I just became really withdrawn and irritable. She broke up with me but we somehow remained friends. I never told her that I'm gay.

Now it's two years later. I'm still best friends with Anna and close with her family. Anna has a little brother "Dave" who is and always has been very flamboyantly gay. I used to be really uncomfortable around him and I remember Anna telling me I had to get over.

Anna's family had a cookout several weeks ago and after it was over everyone except me went to the beach. (I had offered to start cleaning up and meet them down there.) Dave stayed behind and we ended up having sex. I've felt weird and depressed ever since it happened and I feel like I don't know myself anymore.

This morning I got a phone call from Anna. She sounded very quiet and sad. Apparently Dave came to her and confessed what happened because he felt bad. I didn't know what to say to her and just started crying over the phone which I'm humiliated about. She asked if I was gay and like an idiot, I said I didn't know. She asked why it had to be her brother of all people, and I didn't have an answer.

The worst part: Anna's whole family knows -- and her parents were so furious that I betrayed their daughter that they called MY parents to tell them. Now my whole family is trying to get in touch with me, presumably to tell me they hate me.

I don't have any friends besides Anna. So I guess I don't have anyone anymore. I don't know what to do.

tl;dr: My ex-girlfriend and I broke up 2 years ago but stayed close. I slept with her brother, everyone found out, and now I hate myself.