I (28M) ruined my relationship (4+ years) with my fianc? (28F) and her married friends (34F) & (37M)

Two nights ago my fianc? and I went over to her friend?s house to hangout and play a board game with other friends there. As time went on my partner left because she had work in the morning and said I could stay and hang out. We drove separately because I was coming off work when I met them. While playing the board game we were drinking and then after my partner left we started drinking games. As the night went on everyone was starting to get inebriated. And then the last thing I remember is passing out on the couch and then getting up off the couch and going home. I was told today that I made an attempt at her best friend. I have no recollection of speaking to her friend or being inappropriate. I apologized to my partner and her friend and her husband. I want to rebuild their trust but I am lost on what to do as I don?t remember anything inappropriate happening. The only proof of me saying anything inappropriate is the ring doorbell footage of me apologizing to her friend and her telling me to drive safe and let her know when I?m home. I want to rebuild my partners trust and I feel extremely ashamed of what happened. I love my partner with every ounce of me and can imagine doing anything with anyone else, let alone her best friend. What would be the best course of action to try to rebuild everyone?s trust, and mend my relationship with my fianc??
tl;dr I was told I made advances towards my fianc?s best friend, and it?s ruined my relationship with them.


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