Hi there.
I am bipolar. Your wife's erratic behaviour sounds familiar. It must be so hard for you and hats off to you for being so supportive. In all seriousness i think you should get your wife to the doctors and get her back on anti-depressants because from my own experience it is the only thing that will level your wife out a bit. She may not like the idea and deney there is anything wrong but she must understand how this is affecting you. Bipolar is not something she will recover from and it will always be there. Have you spoken to your wife about your concerns? Or are you afraid of hurting her? I think she will listen because she loves you.
I sincerely hope everything goes well and hope i have helped a little.