I'm sorry things went the way they did. It is difficult but you must focus on you. Without a good you, the kids will suffer. When we start to focus on ourselves it makes taking care of others so much easier because: we have boundaries in place, we know we will be okay no matter what happens and the confidence that is projected is empowering to others, we become kinder gentler people, and just all around pleasant to be with. Take care of yourself, you are special and worth it.
You can not change your past, but you can ruin a perfectly good present by worrying about the future.