Can't help being jealous when I constantly see my friends being in photos with the guy I love

I can't help my insecurities and the feeling of jealousy. He has said he loves me and will fight and make sure that we are together and I am so lucky to have a guy like that but my insecurities are stronger than my actual feelings. I feel like I am ruining our relationship because I cant fight those insecurities. When I see pictures of him and my friends, it kills me. No matter how much he shows that he loves me.