Why was I surprised?

I guess I always associate PPD with the hormonal changes that occur with pregnancy and childbirth. It makes perfect sense that fathers can suffer from this, too.

Dads Get Postpartum Depression, Too

The reasons that men experience postpartum
depression may be different than the reasons for women, says Terrence Real, a
couples therapist and author of I Don't Want to Talk About It: Overcoming the
Secret Legacy of Male Depression.
"Generally speaking, a man may be feeling
burdened or entrapped at the prospect of caring for a child or caring for yet
another child," he tells WebMD. "They will feel like all the financial
responsibility is on their shoulders. Or maybe men are suffering withdrawal from
being tended to in their marital relationship," he says. "They are missing their
wives."