Hello ladies!

I have this situation that's been going on for years and it no longer affects me in any way, but I'm still trying to figure out what was the right response to the situation. I want to emphasize that this post may have a lot of negative connotations brought in connection with male sexual strategy and ask men who might be reading this to try and be sympathetic, even if they get a defensive reaction. And I also want to apologize to RPW-savvy men for pointing that out, I just wanted to try and prevent an unnecessary backlash.

So...

This story starts when I was 15. There's this guy (20 at the time, let's call him Mark) who liked my elementary school best friend and went out with her once. I think she liked him back, although she won't admit to it now, but she realized he has no serious intentions and dropped him. In the meantime, he's gotten into a LTR with this girl (let's call her Annie). I met him at a birthday party of a mutual friend, although we knew of each other, we haven't met personally. Annie was also there.

I didn't find him very physically attractive, but he was exhibiting a lot of alpha traits (organizing everyone to play some sorta games, explaining things, dominating the conversation etc.), so I made a comment about him being skinny, which I now realize was a shit test, which he passed. I don't remember how exactly, but he did. And that was that.

A couple of days later he adds me on Facebook and we start chatting. Just innocent friendly chat, but he starts putting up verbal challenges and slowly progresses to being flirty. I was very inexperienced with male attention back then, so I probably responded pretty childishly. I was convinced I was uninterested, although I liked the thrill of being challenged. I refused to ignore him, as I felt it was impolite and he continued to push until I agreed to go out to "hang out," which he quickly renamed into a date as soon as I agreed. I made sure it was in a public space etc.

Long story short, we went out, he tried to kiss me three times, I deflected, he tried to explain me how kissing him would be a good choice, I laughed and asked if he was serious and then he asked if I liked him. And I realized I did. I said, "Yes, but you have a girlfriend." He responded with, "Yeah, that's my problem." Of course, I rejected him and we continued about our day, walking around and being friendly for a while. No more advances. Afterwards, he openly offered me sex in a chat if I ever felt lonely, adding some ridiculous joke in, which I ignored. We stopped communicating so eagerly, until things quieted down completely. Sometimes we met through common friends and chatted it up, but that was it.

Anyways, as time passed I talked to some of my friends and I realized he tried hitting on... well, nearly all females from our common social circles and some unexpected ones from social circles I haven't the slightest idea how he reached. This started making me very uncomfortable. I felt bad for Annie, his girlfriend, who's such a sweetheart.

We met at a convention some months after and he sent me a message, telling me that Annie is getting suspicious and that I should stop checking him out or something. I think he was just trying to reaffirm that his SMV was not lower than mine because I rejected him and remind me that I admitted to being attracted to him. But that message kind of shattered all my illusions. I was hoping that she was fully aware of what he was doing, that it was an open relationship of sorts or that she just accepted it because she thought she couldn't do better. Of course, I was hamstering the guilt of having this knowledge away, of course she didn't know. Ever since I've wanted to tell her, but I never thought it was my place to do so. I wasn't close to her, I never talked to her, even if she believed me she'd just be miserable, she probably intuitively knows but stays in the relationship. But nonetheless I felt guilty.

I have recently (a little more than a year ago) come into contact with both Mark and Annie on the same convention I often run into them at. I talked a bit to Annie and she was really sweet and energetic and cute and could really make you enjoy even a short conversation and feel appreciated in it. I don't know her well at all, but at the very least her facade is wonderful, but I think she's truly a nice person. This sent me on a guilt trip and I confronted Mark over FB. At first, he denied everything, but I told him not to be silly. We were talking privately and if I wanted to send screenshots, I had plenty of old messages and other girlfriends he talked to, my intention wasn't to blackmail him or otherwise use him, I explained what happened and how I felt bad for Annie. I reminded him that she seems wonderful and told him that he is clearly capable of plating a lot of women and since there's a lot of women willing to be in a more open relationships, he really doesn't have to keep one through deceit, especially not such a sweet one. I realize this was a bit impulsive of me, I didn't really think it through, but although it was completely futile, I don't think it had the potential of being harmful, just having a neutral outcome.

He reassured me that we haven't heard from each other in a long while and that he changed his ways. He said I was right, but that was his past self and that Annie is his world now and that he just doesn't want the truth spreading in order not to hurt her unnecessarily and destroy her trust. I didn't quite bite, but there was no use pushing if he wasn't responsive to the message. Sure enough, word travels, and I heard he has in no way changed his ways.

Haven't heard from either of them since. Changed social circles significantly to the point where I might not ever run into them again. But thinking of this still troubles me, wondering what is the correct thing to do in such a situation. I realize I'm not the arbiter of morality and I can't go around fixing everyone's problems and accounting for their own inability to vet partners, but I suppose I just feel some sort of female loyalty. But perhaps it's not that. She's happy with him, so any meddling would actually make her unhappier. So are my motivations truly noble? I'd still say yes, I don't believe LTRs where trust is so fragile that about at least 50 women have the power of breaking it in an instant if the so choose is really of any benefit to the female of that pair.

So, simply to learn from my past, I want to settle this matter once and for all, if possible. With the exception of never agreeing to the date and other mistakes I made in initial contact with him, what do you think I should have done? While insight on the first part of the story is welcome, especially if you feel like I've hamstered something, I mainly want you to focus on the part from the point of me running into Annie and feeling guilty, since that's more recent version of me™, so there might be some points I can improve on.

Also, what prompted me to ask about this now was reading a lot of male-centric TRP and realizing Mark employs it almost religiously. I think he perhaps has been aware (to an extent or completely) of TRP all along. I realized him generally going for much younger girls might not be due to strange sexual inclinations or being unable to do good with older women, but rather conscious knowledge of his elevated SMV in that marketplace. This prompted me to think about how male and female sexual strategies clash and where that leaves us when confronted with males with more of a TRP mindset.

TL;DR: An acquaintance tried to cheat on his girlfriend with me and numerous other girls I know. Meeting his girlfriend made me feel guilty over not sharing knowledge I had, since she's very sweet. Should one interfere in such situations or mind their own business?