Do married men have crushes?

So I've realised that one of my work mates who is married with one child tends to be "too friendly", blushes, tries to make laugh, sits close, tries to impress me and like a lot of signs that screams "he has a crush on you." I don't feel comfortable only because the idea of a man flirting with another woman when he's married triggers me due to personal reasons but can married men who love their wives form crushes? Like if you're in love aren't you blinded and just see that one person? Call me naive but when I am in love no matter how attractive another man is, I only have enough eyes for my man.
Do married men have crushes?
Post Opinion