Quoting Xsecure mommaX:" you probbaly have post partum depression.. its normal and ive had it with each of y kids, lose interest ... [snip!] ... and it doesnt stop as soon as the baby comes out. it takes month before your hormomes get back to normal .. and your body =)"
If she has post partum depression then she needs to get help.
OP you should see a doctor asap. I had/have it too and it caused problems with mine and SO's relationship without me even realizing it. I tried dealing with it on my own or with SO and it wasn't enough, things got worse. Couples therapy and working on my issues I'm having has helped an incredible amount. He is working on hisself as well...slowly..lol but we're both working together. And that is what it takes to overcome relationship obstacles. I'm sure he doesn't realize what you're going through (guys have a harder time putting theirselves in someone else's shoes...at least my SO does lol) so if you could talk to your doctor, maybe he/she can explain things to your SO and give him a better understanding since he doesn't have a clue. Same for couples therapy, they will be fair and help you both understand each other & help point out how to fix things one step at a time. It's worth it if you guys want and will work to save/keep the relationship. Good luck! Keep posted