I disagree. Belldandy has been giving the permission to stay on Earth with Keiichi a couple of times, which is pretty much the ultimate signal that the old man upstairs doesn't disapprove of what's going on. Under those circumstances Keiichi should get the message and proceed forward before it's too late. He might be afraid Belldandy will be taken away one day, but seriously he's already so much in love that I doubt he would miss her any less even if they deepened their relationship. Quite the contrary: If Belldandy was suddenly taken away now, what manner of regrets would he have that he never really showed his affection?