Everyone does it. If it's your ex, he wants to make sure he's off doing his own thing and not trying to get back into your life. His ex? He wants to see if she got fat, or how much uglier her new boyfriend is. He can't help being that little bit curious, or maybe even paranoid. It's a typical guy reaction that whenever something good is happening in their life, they worry about losing it and want to take all the necessary precautions.