threatened

This can have a few meanings. 1.) He threatened to leave her if she continued to hang out with male friends. Or 2.) The man or woman interested in you may feel threatened when they notice they have no chance at dating you or getting close to you as they realize you have your eyes on somebody else and it not be them. They will show lack of interest in you at that moment and begin to ignore the two of you with a defense mechanism to protect themselves and avoid conflict at any and all cost.