Why does he feel like he has to clear his plate?

This guy that I was going with for a short time decided (even after he said he liked me and wanted to be with me) that he needed to end it with me so that he could concentrate more on his studies. I believed him because he had a full-time job, was actively involved with the city plus serving the board of habitat for humanity which he does every weekend because he is the treasurer. We weren't that serious but I trusted that he was doing what he felt was right and that was to let me go because he just could not find the time to spend with me when we wanted to plus I am in school and also have a full plate. He was also going to school as a part of a job assignment so, I understood that and he had been honest with me about things before. I am not in a hurry but If he wanted to come back after he is done with school or feels that he has his ducks in a row, how long will it take for him to initiate contact?