I know there's a million questions on here but please, I really need some advice..?

How often are you "okay" together? It sounds like the negatives seriously outweigh the positives and if that's the case then there's no point in sticking around, it will eventually end in heartbreak. he's left you 3 times already. To me this says that he simply doesn't care. he may come crawling back, but only because he knows he can. It also sounds like you've made up your mind about this man, and the outcome is not good so you're looking for some encouragement. You've got it. leave him and find someone who's worth your time. trust me, you can find someone who is amazing to be with on a daily basis, not just when he feels like it.