Why does he do it.

Heyy y’all! I haven’t been on here in a minute. So I want to ask you guy’s why do my ex keep looking at me in class ? I noticed because I keep having a feeling he is looking at me when I’m looking forward in class and when I turn my head he would look away fast. It only happened like 3 times but he could be doing it more than that I’m not sure. I don’t really pay attention unless I’m having a weird feeling. Also, we have class together because of our major. I don’t tend to look at him because he broke up with me first. I don’t care but then I’m just trying to figure out like what is the problem like if he has something else to say why he can’t tell me or stop looking at me.