I've been trying to be more outgoing lately and I feel I'm doing well.

I suppose I don't have any other options since I'd like to experience the full gamut of life. Recently I saw the girl I was seeing cheat on me with another man, all within my own view. I'm not sure what I did to have her do that, at first I told myself we weren't that exclusive but they ended up leaving together while I was sitting alone in the corner of the bar, almost falling asleep. Is there anything I can do to not be so jealous in this type of situation? I could hardly look, let alone confront them. I'm trying to be optimistic about the situation.