Am I being dumb???? Help please

Ok so my boyfriend of 7 months keeps looking at pictures of girls he thought were cute from his old school he always searches them up on his ig and we have each other’s passwords on Snapchat and things like that but he doesn’t know I have his ig i know he wouldn’t mind cause I don’t have one and he tells me to use him but I tell him no, he always does that at first it didn’t bother me but now is getting annoying I’m so in love with him and he says he’s too but I wouldn’t do that to me he’s the most handsome guy ever. Is that a reason to get mad at him? Should I tell him that’s bothering me? When he met me I wasn’t the jealous type but that just kinda bothers me cause he always looks them up. HELP! And this is also kinda making me feel insecure and I’m usually very happy with myself but those girls usually have big butts and curly hair and I’m the opposite 🙁