Once when I was single...
Let's just say it got very late, her husband had left the nightclub at which we were dancing, and there was a lot of Tequila a hot Mexican night an all too willing very attractive partner.
I felt terrible the next day for a number of reason...but got some relief when her husband said that he actually encouraged her to "Go for it!" This of course was in the Pre death defying STD days...
If the same situation occurred today…and I was single? I really don’t know what I would do probably go home and sleep on it.

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Sex is a tricky thing best left to professionals.