My W has been diagnosed with bi-polar tendencies as well. I have been on here for a couple of months (W can't break EA, don't know how to handle it). We just seperated this week. It's hard; very confusing. I can't tell you much other than if it is bi-polar; she will go through phases. This may be the wrong time to reason with her. You may just need to wait it out till then. I read a book "Loving Bipolar". You may want to pick that up.
