They don't forget. You're not that high on his list of priorities. He takes you foregranted. I bet he knows what time the game starts and when he's supposed to meet his buddies.
I don't actually forget---I just can't remember the exact date. My wife takes no chances--she marks it on the calendar in the kitchen to make sure I know exactly which day it is. All I can ever remember is that it's either the day before or the day after a minor holiday. :( Then again, I can't remember exactly how many years we've been married, but at least i remember the day and month, if not the year.
I always have the gift--just never remember what day to give it to her. LOL
Either he's a jerk or he's genuinely forgetful. You'll have to determine that for yourself.
Then you probably shouldn't be with him. Dating people you know are jerks is bad.
Maybe he's forgetful? Even a guy I Wasn't dating, that I knew for 3 years, he remembered my birthday.