I dunno, if he is actually genuinely busy every day, try saying "ring twice a week, tuesdays and thursdays or something, that's reasonable, right?" and that may be easier for him. However, if he doesn't agree to that, it may be that he just doesn't find you that important.
I also hate to say it but that could also mean that above posters are right in their assumption that he doesn't want people to know about you, in which case you may need to find yourself a more committed man.
I also hate to say it but that could also mean that above posters are right in their assumption that he doesn't want people to know about you, in which case you may need to find yourself a more committed man.