Feeling really depressed and sad

I had a somewhat kind of an affair with my best friend. He was my first. He cheated on his girlfriend with me and they broke up. He told me he just needed to focus on himself and be alone. He brought her to my show i put together one night and I was so hurt. I told her everything that has happened between us and come to find out he's been lying to both of us for so long. I haven't spoken to him in a couple weeks and he has tried once to apologize in person but I'm not really responsive. Come to find out now he's begging for his gf back. I just feel so used and hurt and depressed. Nothing feels right right now and I don't know what to do. My heart is so broken and he was a good friend of mine.. What do I do :(