Making a friend in the hot tub [MFM]

My girlfriend Katy (25) and I (29) went on vacation recently to a nice hotel with a communal hot tub. We spent most of the day in the hot tub, drinking and chatting to other guests. We became pretty friendly with one guy Bill (around 45) who was there alone on business and had a wife at home. Bill was a nice guy but seemed particularly interested in chatting with Katy more than me and often they’d be having their own conversation.

The two of us leave to have dinner, then afterwards decide to head back down to the hot tub for a few more drinks. We put on our bathing suits to go back to the hot tub and Katy has chosen to change into her skimpiest of bikinis, one that rides up her ass and pushes her tits up nicely. We get to the now empty hot tub and guess who shows up just a few minutes later. Bill. The three of us chat and drink for a while and he asks us all sorts of questions about our relationship, our sex life etc.