I have a fair few years in hotels/pubs/inns etc in my younger life, but i really connect with this post. twice I was outright offered a threesome (the good kind for my sexual preference) Both times I declined, once where I just wasn't really interested and once that I don't regret as such, because of staying faithful to the relationship I was in at the time, but 2 of the waitresses propositioned me and I often hope parrallel universe Marv had a fun night. Some of my colleagues though, I don't know why they were in relationships at all, all sorts of shennanigans, but then different stokes I suppose.
The story I always think of was when I caught a barmaid verbally ripping into some customers, an undeniable warning offence and while my manager agreed with me, he just would not make it a formal warning and I was a bit pissed off he'd undemined me. Took a few months there for the penny to drop that he was knocking her off on the sly.
It's a lot less fun when someones husband catches them fellating some guy in the car park though, but I wont dampen the saucy mood.