Male infertility is very common but it's not talked about nearly as much as it should.
Before I got married, I never even knew that you could only get pregnant about 3 days out of the month. It's very important to get those most fertile days right so that you can make the most of them.
Fertility is a tricky subject and you can't count on your doctor to teach you everything you need to know to maximize your chances. You need to learn as much as you can.