Many of us were on the same Roller Coaster Ride from Hell as you and for a long, long time. I never slept for about 2 years. There is not much you can do but try to get through it the best you can. Try reading something other than R books when you can't sleep or do your day work (I HAD to do that since I was a mess by day). Remember "This too shall pass". The torment that comes along with the MLC torture is difficult to handle for anyone, but we all know it. Keep the faith - it will turn out fine for you in time if you stay true to yourself. But the truth is - no matter what - you can't avoid all this - you can't go around it - you have to go through it all to get to the other side. Go read the posts on "Surviving the Big D". Everyone there has walked a mile in your shoes and come out of it stronger and finally at peace for the most part.
As for the children - don't consider yourself a babysitter. You are a father. I know it seems like she is using you, but think of it, instead, as a gift. Some dads have custody. Since you don't - take them every chance you can and show them the best dad you can be. Document all extra visitaion in case there is ever a custody issue - this will help you. But DO NOT do it for that reason. Do it because you love your kids and even if your ex is Mother Theresa - this whole scene is VERY hard on the kids. Don't ever let them be aware that they're in a tug of war.
That's the best advice I can give you. When it comes to the welfare of the kids - you know what is best. Don't ask anyone else.
