"Their colleagues would have to pick up the slack, which would lead to resentfulness, " he says.

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Mixed-weight couples, where one partner is overweight and the other one isn't, have more relationship conflict, including arguments and feelings of anger and resentfulness, than same-weight couples, according to a study by researchers at the University of Puget Sound, in Tacoma, Wash.

WSJ: How to Help an Overweight Partner Lose Weight