How do you get over ending a long term relationship?

He and I were together for 3 years. We have two kids together. I loved him so much I would've done anything for him. He cheated over 20 times. Cheated on me while I was pregnant. He was just terrible to me. So, I finally ended things. But yet, even though I know it's for the best and that I don't deserve that shit at all, I still find myself missing him and wanting us to work.... Will this feeling go away? Does it actually get easier? We lived together and were apart of each other's lives for so long... it just feels weird to me. this was my first long term relationship so maybe that's why I'm handling it hard? Idk. I guess I'm just confused.