Hmmmm.... not sure exactly what your question is for me?
As for your wife's teen diagnosis of bipolar - it's a pretty popular diagnosis these days, there are plenty of legitimate cases, but also plenty of hormone-swinging teens just trying to find their place in the world who are given the label inappropriately. Hard to know if it fits your wife or not from the little bit here.
As for how there might be a libido connection? Certainly depression depresses libido. Also many medical conditions that CAUSE depression can also cause lowered libido. For instance, hypothyroidism can cause both depression and lowered libido. (And, interestingly, there appears to be a statistical connection between bipolar disorder and autoimmune thyroid diseases.)
Also, hormonal fluctuations - in estrogen, testosterone, and progesterone - can be connected to changes in libido in women, and 2 pregnancies might have altered that.
Different methods of birth control can also affect mood and libido - has she changed birth control methods? Is she on birth control now? What was she using when her libido was good?
Don't ignore the simple fact that being a mother of two is a tiring job too and sometimes there's just nothing left to give at the end of the day. How is her libido when you take her away for a romantic weekend for two?
