Maverick, IMO you are right.
I don't mind if my significant other (or date, for that matter) looks at others when not with me. But I find it disrespectful if he does it while with me. On the one hand, we're only human and all (men and wommyn) enjoy looking. On the other hand, it's important to show the 'one we're with' they are special (ie, 'I have eyes for no one but you'). Let's be romantic, for cryin' out loud!!! (BTW, same rules apply for females.)
Note: I hate it when men are with another womin and leer at me. I usually give them the finger or somehow show them how disdainful I am of their behaviour. How dare they (perhaps) make their partner feel insecure or not as attractive as some stranger walking by.
You asked for women's opinions. That's mine. I also have to say that if a person is exceptionally beautiful, I don't mind my partner commenting on it, but not in too lustful (ie. sleazy) a manner.
Okay, honest, a bit insecure, but that's me!
(edited to add: "Discretion is the better part of valour")