You can only control things within your power to control. You can journal and write down all the pro's and con's of your relationship. You can also write down your feelings and why you feel them. Walk through your fear. Hold the fear, and be gentle with yourself. Try not to be hard on yourself with these difficult emotions you are experiencing.
You are a good person and you are worth it. You gave the best you could. It is time to focus on you. You need that. And that focus is sitting with the pain and fear, not running from it, not fighting it, but allowing it. That is the responsibility you have that you can control. Not the issues outside of you,. Right...

I know it is very hard. I am in the process of doing exactly what I have written to you. I am in the same place with so many emotions, and I have been here for 2 months and I don't want to keep feeling the despair and dread I wake up with each day.
I can change that. And how I have outlined above are the ways I have been going about doing it.
Keep reading the boards and writing on the boards. It has helped me.
Good luck.