A variant of this scenario happened to me.
You have an old friend that you've been close to for many years. You've spent a lot of time together. You enjoy each others company. Your old friend introduces you to their significant other and the two of you get along quite well, and eventually become friends too. You like them both individually, and together as a couple. To all outward appearances they seem to get along quite well.
Yeah, with you so far, 100%. I
really liked the significant other. Nikki had kind of known my friend already because she had dated somebody on his sports team, but how she met him properly clawed at me. She sent me a message after seeing my MSN profile (yes) saying "I think I've seen you on campus, I'd like to hang out" but my profile pic was me
with my mate so I assumed it was him she was after, and by the time I met her face to face she'd started going out with him. She was 100% my type and I was full of passionate sexual jealousy.
Two years later.....
However, while at a party which the significant other is not attending, your friend goes off with another person. Later they admit to you that they're having an affair on their significant other.
What happened to me was not that my
friend admitted the affair but the significant other. But she did more than confess an affair.
The first thing Nikki did was tell me that actually, it
had been me that she wanted to hang out with when she sent me that message. Turns out she was in some of my lectures (I knew we were on the same course) sat at the back and she used to get a kick out of me arguing with my lecturers and dissecting some of the established theories (I was a brilliant "angry young man" once, it was another lifetime) and she said "I was kind of sad at the time, and you always looked kind of sad, I thought we could cheer each other up." I told her to stop messing with my head, so she grabbed me by the testicles through my trousers and licked my earlobe, as if to show me she was serious when she said "I wanted you first."
So I got really confused and said words to the effect of "you're moving in with my best friend, this is not good" and her exact words were "would you walk me home and fuck me up the arse?" I stammered that I couldn't do this, she was moving in with my best friend. "I really miss him" she said, to which I replied "you have a funny way of showing it." Turns out that all Nikki's previous boyfriends have wanted to buttfuck her, so she let them. My mate wasn't into that, and this bothered her for some reason. She then went with "Will you walk me home and fuck me normal?" I told her she was missing the point, it wasn't the sodomy that was the problem but the fact she was about to move in with my best friend. I told her I wanted to, but I couldn't. She started playing up that she was just lonely, and asked "will you walk me home and just hold me for a while?" I said I could probably do that but not until the end of the night.
Nikki then unloaded that she knew who "The One" was, and it wasn't my mate. It was her ex-boyfriend, the one who played sports with my best mate. I asked why she was moving in with him if she knew he wasn't "The One" and she didn't know. She also confessed that when her and my mate would have their big arguments from time to time and break up, only to reconcile a few hours later, she would find time to screw someone else. Usually her ex. I was gobsmacked. At the end of the night, I had other priorities and was worried what "holding" could lead to so stayed with my friends long after kicking-out-time, and Nikki went home with her ex.
Do you tell the significant other because they too are your friend? Do you ignore it because you've known your old friend longer or because you don't want to get involved? Do you council your friend against cheating and warn that you'll spill the beans if they do it again? Do you try to break your old friend and his significant other up because you figure maybe you'll get a shot at the significant other if it happens and better you getting that sweet, sweet lovin' than your old friend? Or do you try to break up everyone, even people not involved with this scenario, because if you can't be happy then Goddammit no one can!?
What do you do? What do you do...?
.... yeah. So I basically told everyone I knew practically what had happened - friends, mama, everyone. Practically everyone told me the same thing - if you're his friend, tell him. His future happiness is at stake, he deserves better. You can't keep this kind of thing from him. Everyone except my other best friend, who told me :
"No good can come of telling him. Best case scenario he believes you, they split up over it, she never speaks to you again, and even if he's grateful, he'll hold it against you and it will never be the same between you again. Worst case scenario, he doesn't believe you, they still together and your friendship with him is over."
So... I didn't tell him. A few weeks later the friend that gave me that advice started cheating on
his significant other, funnily enough. 9 years later he's married to the girl and they have a baby girl. Nikki and my other mate are still together, engaged with two little girls. We kind of drifted apart anyway, he let me down pretty badly a few years ago when I was going through shit and needed some support.
I don't know what I regret more, not telling my mate what kind of treacherous headcase he was about to start a new life with, or not fucking the headcase when I had the chance. If I'd decided I was going to tell him, our friendship would likely have been over anyway, might as well get my dick wet first. Probably would have been more trouble than it was worth, but I know from the noises through the wall that she was a demon in bed.