I think he said in an interview somewhere he has no desire to or intention of settling down and starting a family. And he has this idea that women will start to want to do that in their mid-to-late 20s, so he makes it clear to the women he dates that it won’t last. They get to live his lifestyle and whatnot for a few years, then he moves on. He claims to be pretty upfront about it.

The older he gets the creepier it gets, but I suppose if everyone is informed and consenting it isn’t ethically wrong.