I currently work away from home due to being in the Armed Forces. My best mate JK was the best man @ my wedding and is a close family friend. I’ve known JK for years and we’ve been on nights out together for many years so I’m fully aware of his shagging skills. Cut a long story short, I told Caroline I was working the weekend with the idea of surprising her the Fri night & going out for a meal on Saturday. I drove up ( 4.5 hrs commute) & arrived Fri night. I was surprised to see JK’s car parked further down along the street. It was rainy & windy so I came through the back door. Straight away I could hear noises from our bedroom so I slowly crept upstairs with my heart racing. I wasn’t sure what to expect but I had a gut feeling that they were shagging. As I got to the top of the stairs, I had full view of what was unfolding due to the bedroom door being wide open & the lights were dimmed. JK had Caroline on all fours and he was doing her from behind, I could see his massive bellend thrusting into Caroline. He then laid her on her back before going balls deep in her. At this point I felt turned on and had my hands in my boxers wanking slowly. I ended up crawling back downstairs & spending the night in my car as my best mate slept on my bed and ruined my wife.