My mother-in-law gave me a book of essays about how having a baby changes your relationship with your spouse (too bad I didn't have it when I was pregnant the first time around). It's called Blindsided by a Diaper and so far it's pretty interesting. I wouldn't have picked it up myself, but it's still interesting.
Here's a quote I've been, I don't know, meditating on: "(W)hile a woman measures her husband's efforts against what she is doing, most men measure their contributions against what their father did" (from "Not Perfect but Lovin' Him Anyway" by Lisa Earle McLeod).
Obviously this little nugget isn't the magic bullet that will suddenly make my marriage perfect and remove any future issues about division of labor where raising our kids is concerned. Still, it helps me begin to understand how John views his contributions as Dad.