Just want to forget it all :( He left me for someone else

Hey basically I'm really struggling at the moment. I was with my ex about 3 months and yes I know it was a short time but it was very intense , a lot happened and we got through it and he was there for me . I'm 22 and he's 18 so I thought this was really mature of him etc. we got on like a house on fire our personalities completely bounced off each other and we were like best friends . Until recently he went really wierd . Like was being really off with me etc and starting to push me away . I questioned him about this because obvs it was heartbreaking then finally after a week he finished it. I was devastated and went to get my stuff . That night he was ringing and texting me saying he made a huge mistake . He said he just needed a little space but was scared if we have space I will find someone else. So we got back together. That weekend I partied like I never had before and had the time if my life at v festival. For someone who wanted space he text me CONSTANTLY saying don't do anything bad and that he would know about it and he wished he was there!!! This happened all weekend , when I left him alone , then I would say if you miss me see me then he would be a *** and say no space. Well texting constantly wasn't space!!!! So yeah this carried on we split again he begged me back , tried saying can we see each other, I just said your either with me or not and he would beat round the bush so I left it. Then he would say I'm falling at the first hurdle not fighting for the relationship . I went to see him a week later after space and spent time with him, things were ok but not the same. Then the next day he split up with me again!!!!! This time I go down his local and find out he's been seeing this girl for weeks and apparently he was tryin to end it for weeks and I would turn up at his, that's bull I was invited and he was begging me bk :/ so yeah he's with this girl now a week later, and to put it bluntly she's a downgrade and it feels awful how its publicized on Facebook when he was playing us bOth . It's driving me crazy I just want to get over it but it was so sudden and I hate how I hear about how he's so happy and stuff :/ dunno what to do tbh

You both need to know what you want.. and to stand by it. Work toward making the relationship work if you end up being together. The main point of having a relationship is to have a close connection with someone and to work through all the problems to make it work with them. From what I read, it seems he gets insecure of losing you, but is trying to get over you at the same time by rebounding with that girl. He needs to make up his mind, and work actively on making the relationship work with you if he wants you back so badly. He needs to back off and give you space, but if he doesn't, just ignore him because he isn't doing what you asked him to. If you still want to be with him, talk to him more about how you both actively plan to make the relationship work, otherwise, you will be on-again, off-again and repeating this until you both get sick of it.