Actually, my wife has been begging for more children for a while now. We have a boy, 5, and a girl, 4. I love them both a whole bunch (of course), but I am not about to have more. My wife and I could not afford to have more children as this would mean she would have to quit work and our expenses would go up at the same time. (FWIW, my wife works nights and I work days so that the kids are never without a parent in the house.)
She and I were absolute money morons during the first 4 years of our marriage. We are still paying for that now. We have since taken Crown Financial classes and are trying very hard to tidy up our situation. I understand that God instructed us to be fruitful and to multiply, but He also instructs us to be good stewards of what he has given us. Having more children would be irresponsible. We would also be neglecting the stewardship of our most precious gifts, our children.