if you see a T or pdoc that info is confidential. having said that, with your situation with the ex, i'd preface the treatment with "i must be assured you will follow the ethics of the profession and not divulge my seeing you."
if you don't get help i fear that eventually the depression, etc will intensify to the point that your ex will become aware of your fragility anyway and that brings up his possbile intervention for the children.
you sound like a very loving mom. i hope you will consider this avenue to avoid a future heartache of being back in court with your ex. therapy and meds can eliminate all this and help you untangle the reasons for the symptoms. keep us posted, k? we care, i care for you.