It could be part of it or not. No one really knows right now.
One thing I want you to try to wrap your head around...
She has just had a baby. So even though she has been in counseling, she is going to be all over the map emotionally for a while.
Hormones, while not an excuse, really do mess with a woman more than a man realizes.
I can remember, about 4 months after my S was born, and I had had no post partum, just one day, falling apart because the bathroom sink would not come as clean as I wanted it to.
No rhyme, no reason, I just was a total mess. And it lasted for a while after that.
Not to mention that she is dealing with a pretty big issue...
"Acceptance doesn't mean resignation. It means understanding that something is what it is and there's got to be a way through it."--Michael J. Fox