Yes! That's exactly what it was like. An anti-relationship. I think everyone believes that the OW is in her element, but like you've pointed out, that's not always the case, a lot of the time, poor mental wellbeing and low self-esteem have a bit part to play and the affair is a desperate attempt at filling a void.
Another point about an affair being an ‘anti-relationship’ that’s occurred to me as I’ve been reading this thread: when I was targeted by my affair partner (and I use the word ‘targeted’ deliberately, because I very much believe he did target me), I’d just come out of a long term relationship and it was a messy, drawn out break up.
I think an affair was an attractive proposition for me at the time because it really demanded very little emotional input from me. I just had to be up for a few drinks/dinner and some sex. Easy, I could cope with that and not having to give anything of myself emotionally. I was too destroyed by the breakdown of my previous relationship to invest anything of myself too deeply. So in that respect, I suppose it was pretty... vapid?
It was only as I started to piece myself back together and realise I wanted to make a deeper connection with somebody that it became apparent how unsuitable and inappropriate my affair partner was. And that was when I ended it.
In my case he was also senior to me at work (yes, that old chestnut), so there was a power dynamic at play, which he was leveraging to his advantage.
Of course I had a choice whether to be the OW or not. But when you’re in a bad place emotionally and mentally, you don’t make good choices. We all know this, and I’m sure we’ve all made bad choices of some kind when we’ve been at a low point. I think men looking to have affairs know this too, and seek it out in potential partners.
So, I will take responsibility for my actions up to a point. But I also feel a lot of empathy and compassion for who I was back then. What I really needed at the time was some decent mental health support. Unfortunately, instead I ended up with a creepy boss on a power trip, telling me I was clever and gorgeous. I was drowning and miserable and it was the only lifeline I could see that I had.
I see a lot of parallels between mine and your situation OP. I also echo what PPs have said about making women the gatekeepers of men’s desire. Put bluntly, if a married man pursues a single woman, it is not her responsibility to ‘think of his wife and children’, it’s his. In all likelihood, she probably isn’t capable of acting in a compassionate way towards herself, let alone anyone else, which is why she is entering into the affair in the first place.