Hope- I am so sorry you find yourself here. I have been exactly where you are. There are times I look back and wonder how I survived. But when I really think about it, I find my answer. God. I don't know what your beliefs are but for me, I handed my burdens to Him.
I think of this past year and a half as a roller coaster; one I would have rather avoided. I remember the pain was unbearable. That's when I turned to the boards and to my beliefs.
There is no real understanding of your H's behavior. Mine was the same. One minute he would tell me how sorry he was, asking if I would ever take him back. The next minute he turned back into the alien I did not know, like or love.
I vividly remember the day he called to tell me he was leaving. I lost it. I knew it was coming, in fact I told him if he could not stop contact with OW then he needed to move out. Even with that said it hit me like a ton of bricks when it actually happened. I thought I was prepared for it but I wasn't. My point is not to scare you but to tell you it's now a year later and H moving out was the best thing for both of us.
You will get thru this. It may not seem like it today, tomorrow, or the next day but you will. And in the end you will be a much stronger woman. I know I am and I'm d@mn proud of myself.
Me: 39 H: 39 S: 15 M: 18 years Bomb: 6/3/09 H moved out: 10/15/09 H moved back:5/30/10