I (19M) drunkenly messed around with my friend (19M) and regret it. Should I tell my girlfriend (19F)

Last night I went over to my best friend's place and we were drinking and I eventually got fairly drunk and my gay friend was being a bit suggestive. In my less than ideal state of mind decided well here's my chance to try doing stuff with a guy.

There was nothing intimate about it at all and he just did oral on me for a few minutes before I tried doing it on him. I stopped after 2 minutes because I kinda realized what I had done.

Immediately I recognized it had been a terrible idea because I have a girlfriend. All I saw it as, was a chance to experiment with a guy in case I don't get the chance in the future if my girlfriend and I who have been together for nearly 3 years now was to be a forever kind of thing.

Though now I am seriously regretting it and he has said that he wouldn't ever tell anyone about it. I don't know if I should tell my girlfriend or not because it was just a one off thing that I don't have any interest in doing again.

I don't think she would take it well at all even though it meant absolutely nothing to me.

Any advice would be greatly appreciated, thanks

tl;dr: got drunk with gay friend and 5 minutes of oral happened, I regret it and don't know what to do about my girlfriend.