Each of the versions was colored by each character's viewpoint. The husband's more inclined to see what he fears, the wife wants to be innocent and interprets events that Riker was making the moves, Riker wants to be innocent so he interprets events that she was making the moves.
It was a good mystery episode. I also liked the "fight" scenes between Riker and the husband. No one wants to remember losing a fight.
I'd be more inclined to believe the husband's version of the kiss and Riker's version of the fight just based on character history.