I fell like I will never be completely happy ever again in my life no matter how things turn out. I look in the mirror and see a woman fifteen years older than me looking back.
Ok - enough with the pity party!
You will be happy again if YOU decide not to be bitter and to pick yourself up by your bootstraps. You can't control H but you CAN control yourself and what spin you put on things.
(btw, I'm 56 and I'd give anything to have my 43 year old metabolism back but still, I think I look better than I did then).
SO: Step #1 - Let Go Or Be Dragged. Whether or not your marriage will ultimately be saved (and it might) right now you need to let go of your H and focus on making a happy interesting exciting life for you and your girls. If H comes back - he'll just be coming back to a new and improved you. And if he doesn't - the new and improved you will be out there living an exciting life.
If you don't like what you see in the mirror - time for a makeover. New cut, new color? Workout program/diet? Watch a bunch of episodes of What Not To Wear and go shopping for a new wardrobe? Take some chances. Change it up.
Think of some exciting new challenge to take on. Something you have always wanted to do but never thought you could. Train to climb a mountain, or take a standup comedy class, or do what I did - learn to play the drums in a rock band. After the catastrophe you've been living through, those other things aren't so scary anymore, right? Dream!
And don't ASSume anything about your future. You can't know where it will lead. Maybe your H will come crawling back and treat the new exciting you like gold. Maybe you'll divorce and marry a millionaire who will take you off to his beautiful home on Kauai (happened to my ex sister-in-law after my stupid brother dumped her). Maybe you'll be wooed by a series of handsome 6'6" men (happened to me!).
Go on Netflix and stream the movie She Devil. Get an attorney to protect you and your daughters financially. And start imagining a shiny bright new future - and taking steps to create the new you that is going to get there.