Bipolar can definitely seem to be in full remission for a while, even a long while, before re-appearing for some people. Blaming you for the things that are wrong in her life wouldn't necessarily be bipolar but it may be related to delusions or paranoia from the unmedicated bipolar. Or there may be another cause. She needs to see a psychiatrist (pdoc) and a therapist for evaluation and treatment. Is she willing to consider this?