Post-partum depression (which it sounds like she had after the 2nd child is not easy to treat....chemicals in the body get all screwed up (doesn't always happen with the first child)

How did she feel about having children in the first place (even before the 1st one?)

Ok....I was never the motherly type & cannot relate to babies or young kids at all. I knew that going into my marriage & was totally up front about it. I made my H take an active role in our daughters care. I was getting my degree & starting my career. However my feelings had nothing to do with depression. I also was active in caring for our daughter & I was always the one she came to when a problem needed to be solved. Also had a career where most times I could take off work long enough to go watch her activities. Yes, my parents, their neighbor & families from church gladly watched her while I finished my degree. Not having money does add to the depression...long story of my experience when aerospace engineering field crashed & so did my career.....so I understand not having a job & the depression is adds to what is orobably already there.

There may be a lot more going on in your wife's mind that is creating her thoughts that maybe even therapy might not bring out. It wasn't until after I left my H after 33 years of marriage that I was finally able to sort through what I had been experiencing emotionally.

Bottom line.....if it is post-partum depression....that is one thing but I did find out that normal depression is actually anger turned inward. Not always just anger focused at self but anger held internally that one may not even recognize where it is coming from but is definitely there when thoughts & feelings can finally be recognized. Lol....I blew off all the T's in the psych hospitals that kept telling me that. Finally about 4 years after leaving my H & good therapy I was finally able to identify everything that went into that anger.....far deeper than the anger I was aware of.

I know your situation is totally your own situation but sometimes something from anothers experience clicks or at least gives another added insight into possibilities.