Is it okay if your boyfriend thinks other girls are pretty?

So my boyfriend thinks Chachi, the girl from i.aM.mE is pretty. I got pissed and he nearly broke up with me. He thinks it's 'okay' if i think other guys are handsome. Am i taking this the wrong way, or does he not care about me? he's not cheating on me or anything, this is just, like, a summer romance.