Yes, I have felt the same way you do. And I had to finally focus on myself, and feel all the pain (which was unbearable at times) in order to get past it.
Everytime I wanted to call my exabf or check up on him after I moved out, I knew it would just be a distraction from my own feelings.
Good or bad...I have learned over time that I'd rather be sad all alone, than be sad because of what someone else does or does not do.
Al-anon teachings and a good therapist have helped me tremendously. And this forum. It does get easier, but in my experience, first I had to learn to just sit with the pain sometimes.
A hot bath, a good book, a great old movie, a visit to the library...you can have a great time figuring out what you like to do. One day at a time...it takes time.