BF ... I am somewhat like you. My H is gone for long periods of time and the last few times he has come home, I have been so apprehensive and anxious. Like you, I would like to save my marriage, but being alone so much has become kind of acceptable to me. The last visit home was not so bad .. this is what I did ...
I got myself to that place where you know you are strong and can handle anything thrown your way ... with calm, grace and dignity. I kept reminding myself that I would not fall for games and would not defend myself from accusations. I made a determination that no matter what he said, I would listen and not over-react. I prepared myself for the worst while hoping for the best. (I got the worst - he didn't want to be married, didn't want to be a H and wanted a divorce.) I just kept telling myself that I am a rock and I am strong! After preparing myself for days,I managed to do it, but had to remind myself repeatedly of how I wanted to behave.
You can do it .. we have to. We do it for us! Just remember to "act as if" and you'll be able to handle it!
Me: 59 and holding H: :53 Me: 1 S, 1 D, both grown M: 19 T: 23 BD: 9-23-2013