They may not even know they're doing it?

According to Men's Health Magazine, unless you’re a swinger, having sex or being physical with someone else counts as cheating.  But then there’s the fuzzy area between friendship and infidelity—and chances are, your girlfriend sees those shades of gray as more black and white than you do.  “Men aren’t as attuned to identifying ambiguous behaviors as cheating as women are,” says Daniel Kruger, Ph.D., a University of Michigan psychologist, who’s studied gender differences in definitions of infidelity.

So, what you consider totally innocent could be her deal breaker. Here are five signs you might be in an affair without even knowing it:

Photo By: Steve Frost/ThinkStock

TELLING ANOTHER WOMAN ABOUT YOUR RELATIONSHIP TROUBLES



Whether you’re complaining about your girlfriend’s habit of leaving wet towels on the floor —or talking about her distaste for positions in the sack, you'’re revealing weaknesses in your relationship to another woman. And that can, in fact, be an act of intimacy.

CHECKING OUT YOUR EX’S FACEBOOK PAGE



You may genuinely just be interested in seeing what she’'s up to —the same way you’'d check out an old college buddy’'s page. Even so, the assumption will probably be that you’'re flipping through her Spring Break pics or fantasizing about your past.

BUYING A DRINK FOR ANOTHER WOMAN




I'm not talking about purposely sitting near a hot stranger at the bar and ordering her a dirty martini. Even buying your female coworker a cold one could be dangerous. But it could be construed as hitting on someone, especially if you'’re buying a drink just for the woman—not, say, a round of beers for everyone.

TAKING A FEMALE FRIEND TO YOUR 'SPOT'




That Italian restaurant you and your girlfriend always go to? The ice cream joint where you had your first date? Consider those places off-limits—even if you’re just catching up with your childhood best friend, who happens to be a woman.