Hi Craig,
I´m glad you found this board. You will find a lot of support and help here.
I think this is an adjustment phase you´re going through with your wife right now. Maybe her medication need to be adjusted and it´s real important she understands that - if she wants help.
It´s true that many Bi-polar patients don´t want to take the medication because of the side-effects. I have no idea what she is on, because I´m in France and we don´t have the same names for medication. Is this Lithium? I know medication for Bi-polars is usually Lithium with heavy side-effects and decrease in sexuality. But it can be adjusted.
It seems like your wife is going towards a manic phase since you say she keeps going and is instoppable. She is also not taking her medication. Her listnessness and decreased sex-drive could be pointing to a mixed episode, like you say. My advice to you is to talk to your doctor to find out more and get good advice and do read the thread "I need manic depression explained to me a little. Someone please help!" It has lots and lots of infos on the disease. Try not to push your wife. I´m not saying you do, but it usually makes things worse. Take care of yourself and your child and don´t panic.
This will probably pass, but in the meantime, read and get to know the disease you´re dealing with. Information is power. Also, don´t forget yourself and your own needs.
Good luck,