I'm a woman and I can see how she would be able to forgive you. The two of you have been together for 23 yrs and both times you were unfaithful was due to an illness. As long as you learned from the experiences and didn't use the illness to trigger a manic episode to create an opportunity to have sex outside the marriage I would forgive too. Part of her might be tentative in her forgiveness because it is hard but she clearly values you as a partner. I think you need to discuss your fears that she doesn't forgive you with a therapist, because if you remain insecure it can affect your relationship and your mental health stability.