Is it weird if my girlfriend checks out girls and is fine with ?

I mean I've had several ex-es and they would get teary or fight like crazy if they found my or if they saw me look at a girl. But now if there was a hot chick, my girl would be like "She's hot" and I was quite taken aback, and didn't know how to react. She's also cool with me watching , and even tells me that she watch it at times too. Is it strange?