28[M4A]Switzerland-She cheated with me for the first time but never happend again

So all happend 4 months ago,we were 5 of us on vacation,and me and the gf of my friend stayed at home while the other 3 went out,it was one of the rare times where we were only us two alone,so we stsrted talking for a bit,she has been in a relationship with my friend since 7 years now,and tbh always thought she was stunning,at one point she stsrted talking about the fact that they have been together for 7 years and their sex life was slowing down a bit,she only had him never another guy,never thought it would have happend but we make out and had sex...and omg it was so good,at the end we decided to kept it a secret and never talked about it to anyone,so no one knows it happend...