Get the book Babyproofing Your Marriage:
Tons of insight in the sex chapter, including a fairly rational evolutionary explanation why you are getting shot down. The book is a good read, and might help you keep it together instead of doing something you might regret.
Babyproofing Your Marriage talks about how to maintain a good relationship with your partner after a baby. It does assume some gender roles that don't apply in our relationship, but still has a lot of good advice.
The Conscious Parent is the next book I plan to read. The description is really intriguing. It challenges the common assumption that parents know it all and must impart their wisdom upon their children and suggests that parents and children learn together. People enter parenthood with a lot of baggage and dysfunction and they often pass that along to their children. The premise of this book is that children serve as windows to our inner child and help parents grow and develop.