How do I get over my ex?

I really need advice here. My boyfriend and I broke up a few weeks ago. I was so madly in love with him and sadly I still am. He made me feel so important everytime I was with him I just felt wanted and I never felt like that before. I am very insecure and I wanted to be the best I could be for him I spent money on him and had his back no matter what. His "friends" that were girls that DID NO KNOW WHO I WAS. Sent me messages and commented on my photos calling me a whore (I havent ever slept with anyone) saying that I was ugly and it was just terrible. They didnt even know me I have never met them in my life!! I sent him screenshots and he said he would handle it and we got into an argument he said he cried cause he didnt want to lose me. We talked about our future , getting married and everything we had been through so much. Not once did I message any other guy. And he still talked to those girls. He got with a girl 2 days after we broke up and then dumped her for the same girl that was harassing me. He told me he hated her. God man through it all I care so much and he has texted me all day but I just keep ignoring him. What am I doing wrong? I did everything no matter what I was by his side and he left me like I was nothing.