Told his gf about me and I feel like shit

So this guy I’ve been talking to had a gf the whole time and here’s the thing he told me countless times that they did not date and a part of me truly didn’t believe him but I let it slide until I got drunk and snapped and dmed her and she informed me that they have been dating for a year. Now I feel like shit because my intentions were not honest, I did it because I was drunk and angry at him and he texted me saying I ruined his life and I’m riddled with guilt. This isn’t like me at all I’ve never been the type of person to inflict hurt on someone else and idk what to do. I can’t stop thinking about it