My boyfriend of 6 months was never present on weekends or holidays. Is that ok?

He always had too much to do on weekends or holidays and when i told him that i wanted to hang out with him other than during the week, he'd say that he just can't because of x, y, and z. Now he has ended the relationship. Do you think he's married, has committment phobia, didn't feel like he had to try, or that I pressured him too much to stay one weekend that he ended it.