You deserve better.
Pick yourself up, dust yourself off, and find something to do with your free time for the next, I'd say, 4 weeks. Not kidding.
Crochet. Garden. Binge watch. Go to a gym if they're open. Train for a marathon. Reorganize your dresser drawers. Reconnect with friends. Take classes and try to get ahead at work.
It doesn't matter what it is - just, occupy your time and live your life. Be so busy that you don't think about him for much of the day.
Then one day, you'll realize you didn't think about him at all. And when you do, you'll realize that a relationship where he was deceiving you and you were picking fights had no future anyway - so there's nothing to mourn.
But take that time. It does take a while to get over a breakup. It is a form of mourning.