Yeah, God forbid the "ugly girl" actually has a nice, outgoing personality, and that's why he wants her. Where in the world do you get the idea that she must be doing dirty sexual things with him and giving him money? I mean, seriously? That's a mean thing to think. A guy that's a 10 will have a lot of girls after him, if sex and money were all he cared about he could get them without having to get in a relationship with a girl he's not attracted to. There are plenty of hot girls who engage in slutty behavior, no attachment necessary. He clearly likes the girl or he wouldn't be with her, simple as that. He doesn't see it as "dating down". Men do have brains, they recognize other qualities in a girl that they find attractive. You make it seem like visual creature=basic creature, as if they can't see beyond looks. If that were true, it'd be really sad.
Besides, it shouldn't matter to you anyway. Why would you want to date a guy that would be with a girl only for nasty sex and money? His personality would be sh*t.