I’m sorry you’re going through this. I’m dealing with a lot of heartbreak as well and have found a few things that have seemed to help me personally.
1) Unfollow/delete them off of all social media sites.
2) Delete their number from your phone.
3) Move or get rid of things that will be a strong reminder of them.
4) Google “acceptance and commitment therapy.”
5) Read fiction as an escape.
6) This has been the most difficult, but most rewarding thing for me personally: Do new things by yourself. I feel uncomfortable being alone so I’ve made small steps to do things outside of my comfort zone that I wouldn’t normally do. This helps me learn to be less co-dependent. I go shopping alone, treat myself to good food, coffee, or tea alone, explore new hobbies alone, etc… Also, if you aren’t ready to do these things alone, try them with a good friend.