Moira,
   On the off chance you don't realize that the "reply" feature doesn't work on "Our Stories," I'm opening a thread here with a comment for you.

   If you cannot divorce, perhaps you might explore whether there is a way to stay married but live apart.  This is what I for a time considered trying to do with my now-ex.  This would, of course, entail finding a way for the two of you to live separately., and would depend on your finances. I ended up divorcing my now-ex (who is still closeted), but when we first separated, and shared a bank account, it was cheaper to stay married and fund one apartment (where I lived) then to have two separate housing expenses (our house was paid off).   I realize you may not own your home outright (no mortgage), but even then, you might explore alternatives like going to stay with a family member, or house-sitting either locally or nation-wide.    

   Just putting that out there.  But let me add ths: for a long time I told myself that what was holding me back from leaving was financial.  Over time, however, other factors came to weigh more heavily, and the scale tipped so that even though my financial situation was not what I had wanted it to be, I felt I needed to be out, and I left anyway.  I was 64 at the time.  

   I'll also say this: my father was bipolar, and life with him was hell.  My mother endured for decades until his illness crossed the line and he threatened a family member, so she left.   Please know that your husband's mental illness is not your cross to bear, or yours to manage.  I would hazard a guess that most of the time your husband is able to get along in the world, which means he is also capable of seeking help and adhering to a medication regime.  If (like my father) he won't, he simply isn't capable of being a partner, and you have no obligation to stay to honor a partnership.