I am bipolar. A few thoughts.
One thing my psychiatrist told my wife after diagnosis in 2009 was "your greatest difficulty will be deciding on what behaviour is due to bipolar and what is personality".
It seems in your post (if I'm not mistaken) that you believe her "difficult" behaviour is mostly or all due to her bipolar...?...whereas I'd suggest some of it could be due to attitude or marital dissatisfaction or similar sources. E.g. a distant friend of mine had a midlife crisis that caused similar attitude change.
The bipolar aspect of her behaviour can include things like depression, mania, elation, frustration, sensitivity depending on the individual. However, to clarify further, nastiness, lack of respect, lack of empathy, consideration, care, teamwork and ultimatum ("....it's over then") is not among that which is caused by her illness.
I've experienced this myself. My ex would claim my excessive hobby time was due to bipolar. At a counselor meeting the counselor explained that as she didn't have a passion like I did...my ex saw my dedication to my passion as a form of obsession due to bipolar.
I don't hold optimism in your future as her would need to turn around her attitude especially the abuse (silent treatment is a form of abuse) and that is unlikely however professional consultations could give hope.
I think you should ask her to attend relationship counseling. If she won't go then attend alone on the basis that you'll need to be taught how to cope with her in order to move forward with her or seperately.
Either way you deserve better treatment from her imo.
Self preservation is important.