Thank you for all the kind feedback. To answer some questions:

• We don't qualify for any free insurance. I'll check out NAMI. She had been seeing a therapist (likely a psychologist) on her own accord, but I never saw progress. If I find the right professional, I'm confident she would be a willing participant.
• We agreed to have children before marriage. Our first two children were planned, without hesitation.
• She contributes to our household. She cares about our kids' academic performance and how they're treating one another. She participates in family outings. I love her and I know she's still in there somewhere.

Skeezyks' third link is helpful; thank you.

Could anyone recommend information on how to identify and deal with post-partum depression? That seems like my next research topic.