My (34m) partner (31f) of 12 years is leaving me. I let relationship anxiety eat away at me the entire time, it effected my sleep my health and I turned to drugs and alcohol. I got into debt, I told all our friends was unhappy and she stayed with me.

Since last November things started spiraling out of control, encouraged by my therapist I tried to tell her about all my doubts and fears and the gnawing sense of guilt and anxiety that has been ruining my life.

I went in without a plan and when we were drunk, it did not go well, she was devestated. Since then it's been back and forward, were supposed to be remortgaging our house which I currently own so it would be split.

After about five or so awful moments where things have gone to shit then gone back to normal, last weekend things finally started to fall apart for good.

I had started to keep a notebook where I could process my negative thoughts, she found it.

I was away at the time and when I got back she wanted to talk about the things I had written. The most hurtful things were about my constant unhealthy fixation on weather we should break up and my issues around our sex life.

She was looking for me to reassure her and if I had she would have stayed, but I couldn't do it, I can't do it anymore and now she is leaving me.

Last night she said it was over and she would tell her perents tonight, then hand in her notice and move to the city we are from. If she does this she will be gone forever.

I want to get her to stay, to tell her she is the only person I want in the world and that all I want is our life together. That she makes me happy and I am so deeply sorry for the way I have acted.

I'm still twisted up inside when I think of doing this, I want to write her a letter but I'm still terrified of her reading it and agreeing to stay. My anxiety about this relationship is all consuming and I don't know why. I feel like I'm pushing her away because I'm terrified of accepting that I love her and that we are together.

I don't know why I can't do it, when I think of my future without her it's an empty hole, there's no point and I can see the life we would have and desperately desire it. But when it comes to doing what I need to make that future happen I am consumed inside by a twisted feeling of panic.

I don't feel I deserve her, that it's not fair to ask her stay. But I want to, I want to just be happy with the wonderful person I built a life with. I don't understand what is wrong with me that would make me do this.