<human>: Can you provide a brief overview of the text?

Possibly a throwaway is needed, but if anyone I know in real life sees this, they deserve to know how terrible I am.

Nearly four weeks ago I went to a party, and got drunk with my ex-fwb, who subsequently came onto me and we made out, for about a minute, before I stopped it.

I wasn't sure of what happened in the morning due to the amount that I drank, and left without talking to anyone about whether we hooked up, but a week later she texted me asking if I wanted to go to a bonfire, phrased in such a way so as to make it overtly sexual.

At this point I remembered that something definitely happened, and I was almost certain that I kissed her, as I could now remember the events of the first paragraph.

I planned to tell my girlfriend after finals so as not to cripple her emotionally and make her do badly on finals, but before our one year anniversary, which is in a few weeks, specific date withheld for personal security. I now realize that was a mistake, and should have told her as soon as i got the text reminding me.

However, the girl I cheated with or someone at the party told several of my girlfriend's friends, and they told her before I was able to. I don't really know what I'm looking for, as it is neither validation nor comfort, but please tell me how I can, for lack of a better word, reimburse my girlfriend.

 She is likely staying with me, but she is too good of a person for me to leave her unhappy, a far better person than I. (obviously, if I was stupid and selfish enough to go to a party where this happened) I am, or was, taking her on a trip to a place she has wanted to go for some time now, as well as giving many gifts and great affection.

 Obviously if she breaks up with me this will be a moot post, and no longer needed, but if I could be advised by anyone who has had a similar experience, I thank you greatly.
<bot>: Cheated on my girlfriend, if she stays with me I would like advice on how to make her as happy as possible.