Welcome to HealingWell and the Depression forum. Have you ever been dx with depression and are you on any medications or do you have a therapist?
I am sorry you are having a tough time in your life but I do not know that it is something that we are equipped to advice you on as your question is asking us to tell you what to do.
I would really like you to seek professional help if you are struggling with depression issues.
I see the answer to your question in your own words............"forget him, get him out of your system". I know in your heart you realize this is the solution and that it is not easy to do, but my senses tell me you would be wise to walk away and move on with your life.
You can do this. I have faith that you will make the right choice for you.