Hi, I am (22M) in a long term relationship with (22F) that has been going on for 3 years as of now.

Around the start of the relationship (2-3 months in) I went to a party without her and got drunk. I did all kinds of things that would be considered "dealbreakers". (Kissing multiple people, laying down with another girl during down time) We did not discuss things like that prior to the party. But after it, I felt extremely guilty, because I myself wouldn't have approved of such things. So I told her almost all of it (and it was very painfull for us). Except the fact that I proposed in a separate room to engage in sexual stuff with a couple. They refused but I still did propose. (This feels very very wrong for me)

Now, after this, we rebuilt our relationship and until now it's been going very very great. We are following the same studies and are pulling each others up. Celebrating successes together. Going on exchange trips together. Etc etc.. She loves me from all her heart (her words) and I do too.

Except lately there's been a little too much down time for the things filling my brain. As a result, that memory came back and now, I have a choice. Either I tell her, relationship takes a huge hit on trust and I cause her harm. Either I bite the bullet and live with this guilt but that may come back even strongly (she might notice it since it's affecting me physically)

If you are suggesting the first option, how would you approach it? She seems to be living the dream with me right now so I want to make the landing soft enough for her.