Your situation is very difficult but there is a lot that can be done. You say that it was not very good before the divorce but the two of you were living together anyways. There was no love among yourselves, you had or still have no self-esteem, weight problems, neediness and so on. To me it seems that both of you are consciously ignoring that you guys have many individual problems to deal with. Expecting miracles to happen without taking action to solve these problems will not help.
You guys have children and are giving them a bad example of how to solve problems. You can’t love other people if you don’t love yourself first. My friend, you said that life for you has no meaning (“no zest for life, needy, clingy”). This is no way to live. You are afraid, and that is OK.
It is a situational/temporary problem. You can solve it. It does not stay like that forever. Time for a change! Inky and Matt appear to be on the right track. They are talking about the possibility of happiness, and of a new life. Your thought process is stuck; time to let go. It is all very unproductive and negative. Show something good and inspired to yourself and the kids.