The kind of love you have for him is one sided. He’s moved on and you haven’t been able to get him out of your heart. Unrequited love is the most painful kind of love out there to experience. Google and read up on it, go to the site baggage reclaim and read on there as well.
Daisy is right, you need to rid of the hope so you can fully begin to grieve and let go, go through the stages of grief. You need to avoid this man, never see or speak to him again. Like he’s poison to you!
If you can’t do this on your own, please get help. There’s no shame in seeking therapy to help you cope with this and learn to let go in a healthy way.