pbetra, Own only your portion of the demise of your marriage. Do not take on the entire problem. It takes two to make a marriage work and if he's not been there to work on the marriage, then he needs to own his portion. Mlcers always point the finger at others for things that go wrong. They never take responsibility for their portion and even if your marriage was perfect, he would say that you were at fault for it being perfect. Take what he says w/a grain of salt. Work on those areas that you know you may have been "slack" in.
I'm sorry that things aren't going well. Please continue to post. It's difficult and painful when you decide that it's time to separate, but maybe it's best since he's still stuck in the blame game and can't see the forest for the trees.
Please take care of yourself. Try to keep the focus on you.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.