New job + guy seems to be looking at me while he has a girlfriend?

I recently started my new job and I met this guy (same age as me) there wasn’t any flirting or anything just general polite communication and friendly conversations between us but he caught my eye the first time I sew and ever since we first met I’ve been looking at him and I think he’s noticed it (side note, he has a girlfriend so I have no intention of anything)
Strangely enough, I’ve caught him looking at me a few times whenever I wasn’t looking and would glance in his general direction. He’s super nice and friendly, always tells me to have a good day after he or I leave.
New job + guy seems to be looking at me while he has a girlfriend?
Post Opinion