Is it normal that he uploads photos of hot women on instagram?

Yeah if he's a player.

no not at all, he is have too good of a time with himself.

Its normal if you're a fucking asshole who doesn't deserve to even look at a woman, let alone call one his own. I swear, some guys.

I would guess that it might have something to do with whether his partner fulfills his needs.
A normal, healthy, straight, young man is generally a horny creature and his gf may not have as strong a sex drive. In that case, I would imagine he would find ways to get his pleasure, without straying outside the relationship.