Long-time member, have name-changed. I'm really unsure about this so I'd appreciate honest answers. I'm prepared to be flamed.
Back story: as a student I had a part-time job where I worked with a man who I got on with very well, but was not especially attracted to. Nothing went on whilst we worked together.
I eventually left my job, and moved to a new flat elsewhere in town. Ex co-worker owned a car, and offered to help me move a few things. One thing led to another and we ended up having sex. I was flattered, but thought this would just be a one-time thing. However, he was quite keen and so it carried on fairly regularly for a couple of months until I ended it after meeting the man who is now my DH.
Ex co-worker was, and continues to be, in a long-term, monogamous relationship. I was aware of this, but I'm not really here to defend what I did or explain why I did it. I never met the girlfriend, and at the time I had absolutely no interest in 'stealing' her boyfriend or letting her know about the affair in any way.
Fast forward a few years, and I hear through the grapevine that ex co-worker proposed to his girlfriend and they are engaged to be married next year. Ex co-worker has intermittently tried to contact me in the intervening years, but he's apparently lost my number and can only do this though emails that I ignore. (DH has always been aware of everything, and I have never been - or ever will be - unfaithful to him.)
I have no great desire to, but should I/WIBU to now let the fiancée know about the past affair before she married this man? Would she want to know? Or should I just leave well alone?