Mrs C, there are a number of reasons they go for such women, inferior in every way to the wife. Sometimes it's a reflection of their own self image, in the same way as people get certain dog breeds to reflect themselves. Sometimes it's about going for someone who would be grateful for their attention, as they are unlikely to pull much else. And of course in her case she seemed to have money. I have this mental image of her being a bit like the Geraldine James character in Blott on the Landscape, ie very dominant lady of the manor. He's a Blott equivalent without the brains. The lapdog.
Oh and I completely understand what you mean about vile specimens. Snap! Yes I have visions of running into my ex twunt with her in tow. Fortunately it's not happened. I try to practise what I would like to do, ie look her up and down and smirk. I hope, though, I'm never put in that situation.
I hope you are going with someone. So, best foot forward, look stunning, and act happy and relaxed, and when you see them, look through them like they were strangers as opposed to strange. They are merely damaged goods and not worthy of your attention. And if you waver, just think of us on MN falling about laughing looking at the ugly pair of deluded twats.
You are amazing! You are smart, caring, dignified, sassy. Think WWK.. You're up there with the legends of MN.
Routing for you all the way!!