WW - Thankyou for your insights much appreciated!
Yes i think she wants to feel some joy/passion and you're right it seems the chemical imbalance in the brain will prevent this possibly?.
From your list I can see my ex has the following everything except number 6. She still seems interesting in watching sports (loves this) and walking her dog.

1.    Irritability

2.    Anger

3.    Feelings of apathy

4.    The inability to accept criticism

5.    Irrational behaviors

7.    Tremendous amount of shame

8.    Overwhelming feeling of worthlessness.

The thing I don't understand you said your sex drive disappeared when above 20% depressed. I wonder if this is the case with her.
Or if she could get joy from having sex even one night stands. Can you explain when you noticed your sex drive was better?

WW- Wow seems like a good resolution for you both! Stay lifelong friends! You sound relieved with this outcome.