Why,oh why do men do this?

I just saw a photograph of the woman my partner had an affair with and I am shocked. We have never met in person, only spoken on the telephone or rather she shrieked at me. Anyway, like most women who discover an affair I umed that she was far more attractive and ier than myself. How wrong I was. I do not wish to sound arrogant but she looks a good 10 years older than I, is a bleach blonde with an obvious over fondness for stripey blusher finished off with frosted pink lipstick and an outfit circa 1990. Seriously, why would a man who is very image conscious and opinionated on how good women look choose to have an affair with an obvious skank?