Advice on breakup

My ex and I broke up recently after being together 3 years. I’m really struggling to get over him and I need some advice. He and I are really good friends and we both do not have many. The idea of him loving someone else or having a gf or having sex with someone else or just talking to another girl makes me sick. How do you get over a breakup and move on? I want to be able to not love him like I do still.