I can give you a buy one, get two free deal.
As a young buck decades ago I was in my first proper adult relationship. I was 19 and she was mid twenties. Not much in the face but a banging body and loved a hard, no frills fuck so was pretty ideal for a young lad learning his trade!
We went to a house party and there was a girl who had a bit of a reputation. During the evening she asked if I'd be interested in joining her for a bit of fun. I said that it wasn't really an option that evening but would meet her at a local cafe the following morning. So the next morning we both turned up and I told her that whilst I was flattered I really shouldn't as I was seeing this other woman. I remember her telling me "I knew you'd say no. I'd jinxed it by putting on my best underwear". I didn't regret it at the time at all. I took it as a sign of my growing confidence that I could turn down an easy shag, months before I would have shagged first and dealt with any consequence later.
So anyway, spin forward a year or so and I'd split from the first woman, being a young lad it hit me fairly hard. But I was now really good friends with this stunning woman. Again she was a bit older and had recently been going out with a bloke a few years older than her who had been able to spoil her a little bit; and although she wasn't in the slightest bit of the princess type you could see why he'd want to. She was fantastic in just about every way.
Well we started getting close and had had a couple of fumbles. But when my ex got to hear about it she came back on the horizon and said she wanted to give it another go. And like a complete idiot I said yes. It didn't last beyond the time it fucked up my chances with the dream girl. With hindsight I reckon I didn't quite believe I could pull off the big prize. A salient life lesson.
A final coda to the story comes a further year later. I unexpectedly bumped into the "easy" girl I turned down a couple of years before. I made a play and ended up getting knocked back because now she was in a relationship that she was committed to. I ended up fucking her mate that night, but she was an absolute shocker.
A reminder of something I have regretted most of my adult life.
The first long term girlfriend, a story to how we ended up together too long for now, but her parents put a stop to it after 2 years when she went to UNI.
By the time she returned I had met another, who then moved with her parents, directly opposite the first one. Of course it started up again and I should have left the other, cake and eat it and all that, second one got pregnant, did the decent thing, that was it with No1.
Why the regret?
I was seeing No1 for two years before the Uni episode, and we were in tune in every way, never had a row and had a fairly open relationship, her friends were often involved, she liked swallowing cock on a night out, and I mean swallow, it just worked.
I told the story somewhere else of the party while she was grounded, we were fucking in the car in Epping Forest the weekend before, on a cold winters night, but it was daylight when I took her home, to meet her father at the door.
At the party I tried it on with her friend, who could me all sorts, then threw herself at me an hour or so later, she had used the landline to grass me up, and was told to go for it, as I found out when guilt got the better of me and I confessed
I met her in a shop some years later, my marriage was over and I had the boy with me, I kid you not, she burst into tears in that shop, there regret was not only one way, I asked if she would try again, she looked at my son and said she was engaged, turns out to a drummer in a band.
40 odd years later it plays on my mind sometimes, had a little search of media over the years and never found a trace, zilch, I knew the baby had finished it completely, and the choice I made, and regretted it ever since.