If he’s not calling you, it’s because you are not on his mind. If he creates expectations for you, and then doesn’t follow through on little things, he will do same for big things. Be aware of this and realize that he’s okay with disappointing you. Don’t be with someone who doesn’t do what they say they’re going to do. If he’s choosing not to make a simple effort that would put you at ease and bring harmony to a recurring fight, then he doesn’t respect your feelings and needs. “Busy” is another word for “asshole.” “Asshole” is another word for the guy you’re dating. You deserve a fcking phone call.
I'm about to make a wild, extreme and severe relationship rule: the word busy is a load of crap and is most often used by assholes. The word "busy" is the relationship Weapon of Mass Destruction. It seems like a good excuse, but in fact in every silo you uncover, all you're going to find is a man who didn't care enough to call. Remember men are never to busy to get what they want.
Here's something else to think about: calling when you say you're going to is the very first brick in the house you are building of love and trust. If he can't lay this one stupid brick down, you ain't never gonna have a house baby, and it's cold outside.