I am so sorry to hear that.
Very similar happened to me a few years ago. I was doing the Biggest Loser diet and losing weight. Then my partner left me. I thought stuff it and went back to my old bad eating habits and gained all the weight I lost plus heaps more which added to my depression.
On top of this my Mum past away.
I got through it all and now I have a better partner and losing weight again and I can 't wait til I get to my goal weight looking good and bumping into her in a shop and seeing her face to see what she missed out on.
You can do it too.
Lose your weight you want. Look hot and show him it's his loss.
You are better then him so prove it.
Keep posting on here for chats and support, update your weight loss for encouragement and know that you will get through this. Just think, next christmas do you want to be at your goal weight or seeing bigger numbers on the scales. Don't look back with regret, like I did, and wish you stuck with it because what you will gain is soooo much. Look and go to your kids for smiles
Start weight 20/04/2013 = 240kg Goal weight 120kg (total loss 120kg)
It won't happen over night, but if you don't give up it WILL happen.