I was scared for a long time too. My sitch has been going on since January 3rd. A day that will live in infamy for me. I was sorry that I hurt her and blamed myself almost entirely for the situation. I was so scared that she was going to leave me and sometimes I think I sealed my own fate with my ridiculous pursuit. Others have told me her mind was made-up long ago.
Although I did my 180's, I was weak and needy until she actually filed for divorce. That snapped me into reality pretty quickly and she was surprised at the speed with which I began to make financial and other changes.
You've just got to turn that corner and accept your fate. I know it is hard and probably harder with 4 kids rather than only 2, but it is the only way out of the hole. I know, I was in mine for 5 months......