Welcome to the forum. If you read through some of the past posts. you will find that you are definitely not alone.
It sounds like your wife went for a time thinking she could handle the diagnosis and control it on her own. I am not surprised that, that failed. It takes a lot of patience on her part and yours to get to that happy medium where you find the right combination of meds.
Remember, and remind her that the medication can sometimes take 6 weeks or more to see the true affect. The litium may make her zombie like for a while, but tell her to stick it out (with any medication) and see how her body acclimates to it.
I felt terrible for the first month or so when I first started my mood stabilizer but now, a year later I know I can't live without it. And I have to keep up with 3 daughters aged 6, 10 and 15.
Therapy would also be a good resource for both you and your wife. A place to vent those frustrations that go along with BP, without having to take it out on eachother. I know my husband learned some good coping techniques by going to my therapy sessions with me sometimes. It helped teach him more about the disorder.
I hope you both are able to stick it out until the right medication combo is found. It takes a lot of patience!