Why would i want to meet his ex wife (the mother of his child)?

You made yourself look bad by telling him what you did. You came off as very immature and unable to handle adult interaction. You should have used less confrontational language when speaking with him, such as saying something like "I am not sure I feel comfortable meeting your ex-wife." And if you planned to have a serious relationship with this man you would have had to meet her at some point anyway, being as they have a child together. You should seek a childless man to date.