Husband not fulfilling the wife's desires

I have been married for seven and half years now. I have a child, a son, 6 years of age. I want another child but my husband doesn't seem to be interested at all. He hasn't been trying for a baby or even having any kind of physical contact with me for almost two years. I want to know if its valid for a husband to stay away from his wife for that long? What about the wife's desires? If a woman is restricted to obey her husband and never to say NO, why a husband is not bound to take care of his wife's feelings?

To let you know, there are no bad issues between us, no fights, everything is normal between us. I feel im just here to take care of the house and my kid, I feel I'm a maid not a wife.