One person expects career support but doesn’t offer it: Perhaps one of the easiest ways to find selfishness in a relationship is through career support. If one person refuses to support their partner’s career but automatically expects support for their own career, then you are like Houston; you have a problem.
One person is blamed for everything: It takes two people to make a relationship succeed and two to make one fail. Even under circumstances where one person seems clearly at fault (they have an affair, for instance), there are usually reasons for their actions, reasons that point the finger at both parties involved. So, because two people make a relationship succeed and fail, two people should be willing to change, adapt, and give of themselves. If only one person is ever expected to engage in a metamorphosis, the relationship is about as doomed as pretty much all of Franz Kafka’s literary protagonists.
One person must do the heavy lifting: The final way to determine whether a relationship involves someone who is selfish is the heavy lifting: does one person always do it? Is one person expected to always do it? Does the job of “fixing things” fall on one person’s shoulders alone? If the answer is yes to any of these questions, the odds are high that selfishness is involved. The odds are also high that your relationship is in trouble: when one person does all the heavy lifting, they are more likely to drop the ball.