I know how you are feeling right now. It is hard to be alone, when you are use to having someone you love around you. I have found that the weekends a particularly the hardest. At least during the week, I can think about my job and have contact with the people at work to keep me from thinking about my sitch.
I too wanted to find a way the to be done with this pain you are talking about. I have contemplated how my life would be with someone else. I also wanted my W to just go ahead and file the D and be done with it. I even wrote a letter to her telling she had 30 days to start the process and in my state it would be final in another 60 days. I never sent the letter and at this moment in time I am glade that I did not send it. I do not know how my sitch will finally turns out; I will cross the bridge when I get to it. My sitch is improving as we speak, but it's a long way before the end of this book. Each turn of the page changes the ending, so who knows.
You will get to that point some day, hopefully in the very near future. You need to give it some more time. Besides, right now, time is all that have. Think of it as your best ally. Find something to do with your ally. Play golf, shot baskets, go fishing, go to the gym, do something you like to do. I sometimes like to just walk through Lowe's or Home Depot and just look at the stuff. Setting around the house in the chair and thinking about your sitch makes it very easy to start feeling sorry for yourself and how alone you are. It was hard for me at first to do these types of things because, like you, I was always thinking about my sitch. Now my sitch is still in my head, but it is in the back of my mind and not right up front.
Hang in there. It will get better and you will live. I know that this time in your life you my not think it is true, but it is.