Female "Competition" (Please, pleeeease.. grow.up.already)

Being nice and sweet and super polite to a guy but not behaving the same way to his girlfriend or wife when she meets her; shutting her out, talking down to her, leaving her out of conversation, acting like she isn't part of the "in-crowd" along with her boyfriend/husband... pretty freaking clear signal there. Yeah, that woman IS trying to compete with you for your boyfriend/husband's attention.
And what does it mean when a GUY behaves the same way...trying to get your boyfriend/husband's attention and purposely treating you without common courtesy or respect... hmm... gee, what could it mean...
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