heartbroken and can’t seem to get over him...

recently ended things with someone, it was quite serious. we both kinda agreed to end it.. I mean he wasn’t really trying and i gave up arguing with him about it, and i told him he either wanted to be with me or didn’t and that i wasn’t going to keep waiting.. He kept saying that he just needed time, and i didn’t have the guts to tell him myself it’s over.. I knew it was already but i was still holding on.. becuase he really really meant something to me, but i also know he treated me very badly, i didn’t realise how badly until just recently, and stuff he said to me was very very horrible when i never did anything but love him.. So i know we ended things because we needed to.. But i literally cannot stop thinking about him. i know that’s usual after a break up, but i’m so so so close to messaging him everyday and telling him i miss him and i want him back, when i know that’ll be the biggest mistake.. But i can’t stop thinking about him, and it’s stressing me out so much, it’s interfering with other parts of my life, how can i stop? i know there’s no easy way to get over someone, but does anyone have any suggestion on how to make it a bit easier or better distractions?