I posted here yesterday asking for opinions regarding swinging until some gentleman pointed me to correct subreddit.
As I mentioned in that post, the wife and I are open minded to some point, we agreed to have a "free day" where we have sex with whoever we want as long as we don't have to know who were they.
My choice was her sister and her best friend, I didn't see any problems with that until I heard some valid opinions about how I'm playing with fire, I guess they were right.
Anyway it all started last year, we decided to spice things up by having sex with other people on a specific day we agree on, I always had a thing for her 19 years old sister, it seemed that she was physically attracted to me -after yesterday's discussion with the people here I'm almost sure that she's just getting back at her sister since they don't have the best relationship- so I confronted her that I desire her and said she same, the wife and I agreed on a day, she left to "meet her friends" while I was almost sure that she's gonna have some wild sex with her ex boyfriend.