I [M] caught my wife [F] being sexual with a friend, and it has me horny all day

Hello all! This has me horny all day, so I made a separate account to share and talk about it.

I (42m) am happily married with 2 kids to my wife (34f). We are still sexual, though not nearly as much as before. Last night, we had a big party at our place. The kids were with the grandparents, so we went all out. Lots of food, lots of drinking, etc. Several people drank too much to drive so they passed out around the house. A couple of our close friends ended up falling asleep in our room on our bed, so my wife and I, who ended up being the last to pass out, took what ever space around the house there was.

As the very early morning came, various people began getting their things and leaving. Eventually, it ended up being my wife and a friend of mine (48m) laying on the sofa in the living area. Everyone else had cleared out of there. At some point, I woke up to check around the house. I peaked in to the living room, and saw the two of them alone in the room, cuddled up facing each other. I heard whispering, so I kept quiet and out of sight so I could listen in. I was peaking around the corner for over 30 minutes.