Has your wife been evaluated for post-partum depression? It sounds a lot like what my wife went through after our 2nd child was born. She was diagnosed and put on A/D's and it make a world of difference in her attitude towards everything.
Her previous (and only) therapist said she had OCD tendencies an focuses on the negatives constantly, to the point of them becoming debilitating. They said she may need medicine, but she's strongly against taking any and believes things can be fixed with the mind.
She also informed me that she has her period again. This is the third time in six weeks. I've been monitoring her cycle/moods for the last five months. It's clear that she's very irritable, short, and crabby when she has her period. I'm guessing this irregular cycle is really messing with her head as well.
M34 W35 S5 S2 T10 M6 on/off over the years including her A Recently- Nov 2015 bomb Nov 2015-Feb 2016 Reconciling Feb bomb March-April Reconciling May - bomb Mid-May I tell her I'm done