Take a closer look at the timeline. From what little we saw of Gia's daughter, she was more than a few months old -- I think there was a shot of her toddling about at one point. The impression I got from Gia's conversation was that the depression (which probably lasted a few months or more) made her feel disconnected with her daughter even after it passed: I wasn't there for the first moments, so how am I supposed to be there for any of them?

My major question from that conservation: did she go undiagnosed? A lot of post-partums manage to hide it pretty well right up until someone walks in at the wrong moment. Gia may have had enough control to hire the nannies and walk away. Her pride/ego could have easily kept her from telling her husband -- ever. Depressive logic: I'm out of the picture, so everything's under control...

None of which changes the fact that Gia herself is an overindulged narcissist with a full boatload of other mental issues, first among those being No One Else Has A Life, I Want Total Liberty Without Responsibility, And I'm The Sole Person Entitled To Happiness.

Divorce? I'm still having troubling believing she found someone who'd marry her. (Either he has virtually no ego or the one skill she has is blackmail...)