Mental illness and relationships!

As a listener I have been privileged to be able to speak to many members and guests who have allowed me to hear about their lives and one area that often crops up is the struggle either they themselves or a loved one faces with mental illness. This alone would be challenging enough, but often I see how this affects their relationships, I am thinking more of romantic relationships really, but it does apply across all relationships. So how do you as a partner best support a loved one with a mental illness while taking care of your own needs, and how as a sufferer do you make your partner aware of your limitations and how has your illness affected your romantic relationships - both success stories and those where progress is yet to be made are welcome.