Mamma Bear - no matter her age and her IQ he has still affaired down - there will be some underlying "neediness" in her that prevented her having a boundary about married men.
My H's OW is attractive enough (if you don't mind women who resemble horses), brunette although she is much younger, possibly intelligent in some ways, works for the same company (big surprise!!!), but I know that she has severe "Daddy issues" in that she grew up with only her mother and won't even speak about her father (can see why H was an attractive option - seemingly committed family man (not any more!!) but also raises the question why would she be willing to let him leave 2 very small children for her - very selfish and self-serving (perhaps jealous of my life, too) , she is very controlling and jealous and somewhat pathetic. Traits that I do not share in any major way (everyone can be those things about some areas of their lives, but I know I am usually not those things and was not with H (otherwise I would have suspected the affair much earlier).
So whatever they say, they most often have "affaired down" in some way.