Doesn’t bother me at all.
There was once when I was on my way to a hotel meeting a WG, who called and asked if I was nearby. I was a couple of minutes away, anyway as I was at the hotel lift door, a chap walked out and we clocked each other. A few minutes into our meeting, the WG’s phone rang and I overhead she confirmed to him that it was me at the lift / hotel lobby. This WG gave me her real name and personal email, as she wanted me to send her some pictures that I took. I checked her out on FB and there he was, her partner.
Another time, incall at this WG’s flat, she was wearing an engagement ring throughout our meeting. In her room there’s a box labelled ‘wedding stuff’ so obviously she had been planning her wedding. Half way through our meeting I suggested to go into the living room (door closed), but she said no cos there’s somebody in there. After I left, I was walking to my car which was parked a street away, and I saw her and a chap driving off together, so obviously that ‘somebody’ in the living room, was her fiancé.
Gave me a power trip and I very much enjoyed that.
I wouldn’t mind trying a bit of cuckolding; having said that I wouldn’t actively looking for the opportunity.