It wasn't just that she was younger, but that she was Asian. The woman he had the affair with years before was also Asian. It's a surfer thing, having an Asian girlfriend.
As for older guys contacting you on dating sites - part of it is they all think they look younger than they really do lol! And yes, it's also a red flag for MLC (whether or not they are WASs). That being said, I dated men who were much younger than me, so it's not really fair for me to judge. I wouldn't completely rule out a guy because he was older, but he'd have to be pretty fit and healthy to offset the risk of ending up nursing a feeble old man.