Noo not atall, I admire the female body myself, I think its beautiful and the photos are often motivation too anyway!
The thing is there are always going to be other girls around and there are pictures of other women everywhere so you can’t stop anyone/the guy that you’re with from looking at them and if he says someone else is attractive its usually just appreciating beauty - The key is communication though so if you feel he is saying it to you a bit too much or disrespectfully if he knows it might make you down then tell him - Say it makes you feel uncomfortable and you’d prefer it if he didn’t say that to you
You’re not being stupid, its a natural thing to feel that urge to compare, especially with how things are with women and the media these days.I think of it this way, Look at yourself, you are YOU, you are the only one that owns yourself and your body and you can make it look any way that you want. You’re never going to be anybody else and guess what, Your boyfriend is with YOU! He loves you otherwise he wouldn’t be with you or wouldn’t have shown an interest in the first place right? he’s not with the girl in the photo.
Sorry for the essay but I feel that so many girls feel this same thing, if you can brush it off/admire them too then do so but if it makes you really uncomfortable, tell them xxx