Does self-control increase or decrease relationship quality?

Self control refers to behave in certain ways when you're facing temptation.

Those behaviours are usually expected, which are social constructed to fulfill the social expectation. When the couple are highly self controlled, they may already have same kind of values, expectation, responsibility, etc. Another words, they may have less conflicts compare with other couples, in the article they called complementarity couple, they have quite different self control.

Lilac Kamiya

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Does self-control increase or decrease relationship quality?

What combination of partners' trait self-control levels produces the best relationship outcomes? The authors tested three hypotheses—complementarity (large difference in trait self-control scores), similarity (small difference in self-control scores), and totality (large sum of self-control scores)—in three diverse samples: friends, dating partners, and married couples living in the United States and the Netherlands who were tracked cross-sectionally and longitudinally. Results consistently favored the totality model: the more total self-control, the better the relationship fared. Multiple benefits were found for having mutually high self-control, including relationship satisfaction, forgiveness, secure attachment, accommodation, healthy and committed styles of loving, smooth daily interactions, absence of conflict, and absence of feeling rejected. These effects might be due to high-self-control partners' use of accommodation when there is miscommunication or problems in the relationship. Additionally, partners might "outsource" self-control to each other; hence, having a partner with higher self-control enables more outsourcing.

Source: "The Sum of Friends' and Lovers' Self-Control Scores Predicts Relationship Quality" from Social Psychological and Personality Science