You’ve explained it in every way but directly, I think. So now it’s time to tell him as plainly as you can.
“Steve (I assume his name is Steve), I don’t like it when you keep liking other girls’ pictures on Facebook, especially because you never like mine. It hurts my self esteem and makes me feel like you don’t care as much about me as I want you to.”
If you haven’t told him in as clear a way as the one I laid out above (you haven’t), then you need to do so immediately. If he keeps doing it after you laid it out plainly, then he’s an idiot and doesn’t realize how hurtful he’s being. Which means you should break up with him. But before you do that, be clear. Tell him plain and put it on him to fix his jealousy-inducing immaturity.