I know you have a history together, but I struggle with the concept of using your XH as a source of support. Would you feel the same way if he was married to the OW? I do think he's been callous, but I also think you need to lower your expectations about what role he should play in your life. To be brutally honest (and sorry about this), you probably mean less to him than he does to you, so he doesn't really feel the urge to be there for you. He's someone else's rock now.
I hope the ADs work for you. Give them a chance to settle before you abandon them. A little jitteriness should disperse over time.
You cannot be lonely if you like the person you're alone with. Dr. Wayne Dyer