Why do some exes downgrade horribly?

My friend recently broke up with her ex , they’re both in their 30s and she is absolutely gorgeous. He then started seeing a woman 20 years older than him, married and no offence , ugly and crazy. Can also barely speak English. And I call her ugly not only because of her looks but because she reached out to my friend manipulating her and questioning her about him, when she’s 20 years older than her and should be focusing on her husband.

Why would a man want to embarrass himself like this and downgrade so badly?
Why do some exes downgrade horribly?
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