Twice. One time found her being fucked at a festival after she disappeared, second time found her being fucked while we were camping, but the guy staying next door.
My wife did the same thing after fucking at a festival that we attended. Had to take a shuttle back to our hotel, and she left some cum on the shuttle seat.
Two of my wife's guy friends that she went to school/grew up with are. They both live out of state and will randomly stop by the house for a "visit" whenever one of them is in town visiting family.
They're the only ones that my wife personally knows that know we dabble in the LS.