My wife and I have been married 26+ years and she has been mentally ill through all of it. I know well what you are going through. My best advice to you is to keep trying therapists until you find one that she really trusts. Often the things I tell my wife (over and over) go in one ear and out the other. When the therapist she trusts tells her the same thing (like keep taking your meds) she seems to listen to him.
I know when you are at the bottom things seem hopeless. Please hang in there.
My gf of almost 9 years is dealing with this sort of thing. It gets pretty bad sometimes, especially the paranoia, which has no basis in reality. It's a struggle, but I love her.
Based on my observations, sometimes I think that all women are crazy to a certain extent (except mom). Sorry ladies. Not to make light of it, but your brains are bathed in a different set of chemicals...