Having sex with my wife’s younger sister and her best friend

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.

The wife and I are thinking about swapping with other people to spice things up, experienced opinions are needed

We are open minded to some point, I don't mind her fucking someone else and she doesn't either, we agreed to have a "free day" every now and then, where we could have sex with whoever we want as long as we don't tell each other who we had sex with, honestly I fucked her young sister and her best friend, and I suspect that she had sex with her ex boyfriend, but now we are thinking about taking it to the next step, which is swapping with other couples in the same place, I'm afraid that we're going to regret it once she sees me with her own eyes fucking another woman, the same goes for me.

Anyone had any similar experience? Is it regrettable? How did it feel? Was it awkward?

I’m [M]arried but I love how I get bent over.

I'm a guy who's married to his college sweetheart, living a normal life, you know nothing interesting, until that night which changed my whole life…

I had to stay late at the office, I usually finish at 6 pm but that night I stayed till 9 or something, I called the wife and told her to prepare the dinner and I'm coming home.

I took my stuff, closed my office and walked in the dark hallways, everyone's left it was late, first I thought that I was hearing things, but as I'm getting closer to the kitchen I was sure that I was hearing some muffled grunting, I got scared and walked slowly to see what the hell is going on, I took a peek into the kitchen and found our security man fucking some young dude, just to keep you alive in the story, no one really knew our security guy, we only knew some stories about how he used to work as a construction worker then a security guy for some bank and after that he was divorced, he's a huge guy in his 50's, brown, and has some grey hair on his head and body.

I gangbanged my wife with my 2 best buddies.

We've been married for some time now, I knew her since college, she's tans regularly so she has this bronze skin -which I madly love – she dyes her hair red and has a fairly attractive body, this may sound weird but she paints her nipples black so they would match her bronze skin! She's always been into doing "unusual things" like opening the door topless to the delivery kid just to have a laugh, don't get me wrong, I'm totally ok with this, I giggle of the thought of the kids jerking off just because they saw a pair of boobs.

Anyway, we have sex on regular basis, I even have to masturbate an hour prior to having sex just to last longer because she never gets enough, so one day while at the office, she called me and said that she has a wild idea of having a gangbang with my 2 best friends, I thought she was kidding so I said ok, when I came home she was already doing a bath with some kind of cocoa creams for a smoother skin, I asked her what's that all about, she said she's ready for the group sex, I told her that I thought she was kidding and she didn't say anything, she kept telling me about it for a whole week until I said fuck it, I told her that I agree, she was happy to hear that, I thought out loud that I need to get some condoms, she said she wants to have it raw, I was shocked to be honest, I refused at first, but agreed later on because I know that they are clean and she's on her pills.