I wouldn't say he is being selfish at all. It sounds like he's just uncomfortable with it... and a recurring theme on these boards is to not make someone/be made to do something they don't feel right in. Personally, I don't really see the point of phone sex so I'd probably be the same way, but to each their own. I'm not here to judge.
I agree that there are plenty of ways to compromise. The webcam idea sounds like the best way, that way you guys can actually see AND talk to each other instead of just talking on the phone. Seeing you in action will probably turn him on more, and having that almost face to face interaction might make him feel less weird about it.