<human>: Can you give me the gist of the text in a nutshell?

Been in a relationship for seven months, and overall it's going great. Last night I went out with a group of friends without the gf, and I've had a crush on one of them for a long time. She started talking about her problems with her current boyfriend, and later that night (on the verge of blacking out) I cornered her, confessed my long held feelings, got a little handsy, and just generally made a complete ass of myself. 

I'm terrified that this is going to be a deal breaker for my relationship. Despite what I said last night, I have no wish to see it end and can't believe what a stupid fucking mistake I made. I've resolved to tell my gf as soon as possible, but I have no idea what to say. 

I've never gotten even this close to cheating on someone, and I just don't know what to do. Any advice or experiences, especially from someone who's been in my gf's shoes, would be greatly appreciated.
<bot>: confessed feelings I've had for a friend at a bar, freaking out about how to tell my girlfriend and salvage the relationship