Is it a relationship-ending situation when your boyfriend looks at another girl, or is it just human nature?

Let's say your boyfriend is looking at another girl while you're there. He doesn't say anything inappropriate, but you see his eyes wandering around. Some people say it's harmless and part of being human. Others think it's a sign of disrespect, especially in a serious relationship. Do you think this behavior is a red flag or something to ignore?

Is it a relationship-ending situation when your boyfriend looks at another girl, or is it just human nature?
Post Opinion