He Makes Excuses to Not See You
When a guy is really into you, he will look for ways to spend time with you. He will look for ways to spend time together, not apart. If he has a somewhat busy schedule, he will do his best to make time for you. And if he can't seem to find at least a few hours a week for you then it means either he doesn't really like you as much as he says he does or he shouldn't be dating at all, because one can't reasonably expect to sustain a healthy relationship with someone when there's very little communication/interaction.
“Too busy” usually just means he doesn't like you enough to invest in a relationship with you. Otherwise, if you he thinks he is usually “too busy” to date, then he just shouldn't.
One good indication he truly loves spending with you is if he is willing to go with you when you run errands. When you go grocery shopping and invite, if he says yes then he just likes being around you, no matter what you do.