I need opinions!!😓

My partner and I have been together for over 2 years now, we are common law and we have a kid together. We have a great relationship. But there's one thing that he has that drives me nuts!!

Sometimes I feel like im overreacting but other times it really bothers me so I need your opinions!

He uses Instagram basically only to follow Instagram models and their always half-naked and he looks at them all the time and at first it really bothered me but he wouldn't get rid of them so eventually I just got used to it but now I just saw that he was messaging one of them .. and I do realize that these women are halfway across the world but it still really bothered me because he sent her a message saying " I know you're too busy being sexy" or something of the sort. I know he isn't cheating on me or ever will.. but the fact that he watches these women so closely and is now messaging them just hurts me so much especially when he knows how self conscious I am..

Soo.. opinions?? Am I overreacting? If so how do you suggest I deal with this?