How to make a marriage work even if i'm gay?

I am very serious about this so please do the same. I am at the time where I am in the beginning of a career and want to get settled into a family. I have always wanted a child and a wife, a normal life. I, however, have one obstacle. I am, by birth, gay. I have never told anyone and have no plans of doing so. I often think about how I am going to cultivate a functioning family with my homosexuality. I know I can always get married and adopt but there is once again, another problem. I would feel selfish because I am taking my wife away from a very adult act, sex. She would certainly figure something out when I don't get "up". I could put all of my feelings behind once I get married but arousal, children, etc would be almost non-existent. What can I do about this? I don't want to live life single, I don't want to rely on my one income, I want to make someone else happy. How can I make it work?