Bipolar Relationship

Its going to be a lot of hard work and patience. If leaving or "dealing with it" are your two options then leave. If leaving or learning to be a partner with someone who is mentally ill are your options then see if you are capable of doing that; and if not then leave. As far as what you SHOULD do in general - you should see a therapist for YOU. You should take care of yourself. You should learn where to draw your lines and you should learn how to maintain your mental health. Then you should talk with your partner about what their expectations are from you and what yours are from them. Can you both be practical? Can you both work together? Can you come up with a plan for when the ill person loses stability? That is just the beginning. Its not easy.

If you feel that person might cause harm to you leave

I think it is best to consult a shrink.