Replace the question mark with a number

A man and a woman had been married some time when the woman began to question her husband. "I know you've been with a lot of woman before. How many were there?"
The husband replied, "Look, I don't want to upset you, there were many. Let's just leave it alone."
The wife continued to beg and plead.
Finally, the husband gave in. "Let's see." he said "There was one, two, three, four, five, six, you, eight, nine..."