I dated a guy for two years while I was in grad school. WE lived together part of that time.
He used punctuality as a stick to beat me with. Experienced now, I can see this coming in anew relationship. He would ask how long will I spend in my study groups. Well, not only is it possible that a study group will go over time, but I guess I forgot I was in grad school to do the best of my ability not be a slave to some one else's insecurities. Well, you got it, this guy, my bf, felt thouroughly entitled to show up whereever the group took place to ask why aren't we finished. He would sit around and wait, not so patiently until we wrappred up. If it was at someone's place, he would get a phone number out of me and he would call 10 minutes after proposed quitting time like clockwork. And complain, of course.
Also if I went out with friends he would also ask for a time when I would be back. I would give him an etimated time. If I was once again more than 10 minutes late, He was in a bad mood. He tried to come off as easy going by saying you could have called. Oh, really now, this was during the pre cellphone era when phone booths were the offices of drug dealers and he expected me to spend time (which would make me even later) to find a working phone booth just to call him.
You can blame me as much as you want for letting it happen. But these experiences only free me to say fuck off sooner rather than later.