Most Helpful Guy
I know it probably goes against the question, but I honestly can't see myself ever getting into that situation. I have an ego, sure, but it's fueled more by self confidence than outside stimulus such as this.
I wouldn't keep her on a "leash" just to feed my ego. Once the relationship is over, I'd let her go. If we broke up, there would obviously have been a reason, and when she found somebody new, I would be happy for her, in an offhand kind of a way. Like, "Oh, she's with somebody else, cool. Now to finish whatever I'm doing."
Any man who behaves such as in your example is very insecure and childish, in my opinion. I apologize if that's not the answer you're looking for, but it's how I feel.
Most Helpful Girl
This guy you're describing sounds like a douche, so in all honesty he probably wouldn't care so don't waste your time.