I think if it was a Thai, or even a foreigner who was a little more grounded, it would have been fine. Thai people don't view relationships the same way as Westerners do. I imagine that if it was a Thai man, he probably would have been a little more switched on to the fact that it was a lot more of a financial relationship than a romantic one (he pays, she cooks, cleans and provides sex). Perhaps the foreign man expected the 16 year old girl to behave like someone deeply in love, and when she did not, he couldn't take it. It seems as though there must be some element where the reality did not match the expectations, since he arranged it, moved there, then changed his mind. Perhaps he thought that the whole family would be serving him, but it was the other way round. Or perhaps the girl offered only sex and nothing else. Who knows?