I want to let go but.....

So like 4 or 5 weeks ago I started talking to this guy. He was just so tall, nice, sexy and he was the perfect gentleman. I thought him and I was having a good thing building up. He told me he was good through a break up. And i was ok with that. After like the fourth week we kinda took part in oral sex and fingering in a stairwell at our school, but before we met up I saw him talking to his ex and they was gone for like 30 minutes. Then he met up with me. And we had oral sex. After we was done I wanted to ask him what was they doing or who was that girl but I did want to ruin the moment so I didn't. I texted him that night about it and he told me she wanted to get back together with him and she wants a second chance. Then he said I have to pic which one I want. So that kinda made me feel like nothing and I have to compete just to be happy. He stopped texting me that night so I just assumed he was sleeping. Next nothing, he completely stopped but he's still reading me snap chat stories. I don't know what I want to do like i really like him but I also want to forget about him. I just don't know anymore I need help 😫😫😫😫😫😫😫😫😫😫😫😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😭😵😭😭