awww hugs hun. Seriously, I was in this situation 3 years ago and I felt so awful, it really was the worst time in my life, (my nanny died 3 months after me and my ex split too so it really was awful) but now I am engaged to a wonderful man who would do anything for me and my son. It just makes my heart melt when I see my son and my other half outside doing the gardening together or playing together

Things WILL get better.
I know its hard to hear, but if your ex doesnt care about his kids and he says he wants to move away and be with his family then let him. Be strong! If neither of you get on and he doesnt care about his children let him go. I know your babies love their dad and its heart breaking when they cry for their dad but having one happy mummy looking after them and showing them unconditional love is much better than having 2 unhappy parents! I know its easy for me to say but you need to do what is right for your children. If your ex mentions not caring about his kids again tell him to do one then!!!

You dont need him!
Have you contacted the council and jobcentre about sorting out your money like i said before? If you do that, it really will help with your confidence knowing that YOU are the one looking after your children and that you dont need to rely on your ex at all!
Try and limit contact with your ex aswell. Maybe try and sort out an agreement so that he sees the children just on weekends, maybe he take them out for an hour or 2. That way your children get to see him regularly but you dont have to see him every day! If you need to talk hun, feel free to pm me, i dont mind xxx