Dealing with brutal heartbreak

So he never told me he was unhappy. We were literally so good, happy couple for two years and three months. We were in a rough patch at the time, but I never thought it would end like how it did. He then asks for a break in person, and then a week later dumps me over text. I've tried so hard to get over it, because I hate being sad. But it seems every weekend I get shot down again. At first I wasn't happy but I respected him. I then spoke to him a week after that asking if he wanted any of his stuff back, we ended up talking and he acted like a smart ass and totally disrespected me, it was a part I never saw in him. After that I was so mad but glad bc he helped me to get over him, I lost all respect. The following week, long story short, he said this girl (who has kind of been in the picture through all this, someone I suspected and don't like) he said ".... has always been my girl" and then implied I was the downgrade and she was not. After that I blocked him on everything. But my best friend was stupid enough to show me a snapchat story of his, and it was three girls with the caption 'upgrades'.