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Breaking bread with an ex is apparently likely to stir up your partner's jealousy more than any other activity, including trading emails, talking on the phone, or grabbing a cup of coffee. (Though probably not as much as actually sleeping with an ex, but that goes without saying.)

The finding is from a study of 52 men and 27 women published in the journal PLoS One, and both men and women said that sharing a meal was particularly likely to spark the ire of the green-eyed monster. (And just for the record, most people found that talking on the phone was more jealousy-inducing than if their partner traded email with an ex.)

So what's so sexy about food? While there's a dating service called "It's Just Lunch"—based on the premise that lunch is a setting relatively free of sexual overtones—apparently more people are imagining the scene from 9 1/2 weeks in which Mickey Rourke and Kim Basinger smear food all over their bodies, and well, you know.

How about you: Would you be more jealous if your partner had lunch with an ex as opposed to say, coffee?