The Big Picture of Relationship Satisfaction Research
"What makes romantic relationships succeed?" is one of the most extensively studied questions in psychology. Since the 1970s, thousands of studies have accumulated, and their findings have been integrated through multiple meta-analyses.
Le et al. (2010) conducted a meta-analysis synthesizing 137 studies, organizing the factors that predict whether a relationship dissolves. Additionally, Karney & Bradbury (1995)'s Vulnerability-Stress-Adaptation Model proposed three categories of factors determining relationship quality (individual vulnerabilities, external stressors, and adaptive processes) and remains widely referenced today.
This article draws on these bodies of research to walk through the main factors linked to relationship satisfaction, area by area. Which factor comes out strongest shifts with study design and measurement, so no ranking is implied here. The five covered below are the ones that keep coming up: communication quality, personality trait compatibility, joint coping with external stress, commitment and investment, and sexual satisfaction.
Communication Quality
Gottman's (1994) long-running observational work and Lavner & Bradbury's (2010) longitudinal studies consistently demonstrate that communication quality is closely tied to relationship satisfaction.
Constructive communication: Openly discussing problems and striving to understand each other's perspectives. Dialogue patterns like "Tell me how you feel" and "This is how I feel." Its association with relationship satisfaction is reported to be consistently strong across studies.
Destructive communication: Criticism, contempt, defensiveness, and stonewalling (Gottman's Four Horsemen). Couples with high frequencies of these behaviors are markedly more likely to end up separating.
Everyday positive interactions: The quality of daily exchanges during non-problematic times also matters. Showing interest in your partner's stories, performing small kindnesses, verbalizing gratitude. Gottman calls this the "Emotional Bank Account," explaining that daily "deposits" make "withdrawals" possible during crises.
In relation to the Big Five, people high in agreeableness tend toward constructive communication, while those high in neuroticism tend to fall into destructive communication patterns.
Personality Trait Compatibility
Malouff et al. (2010)'s meta-analysis of 19 samples with 3,848 participants demonstrated that Big Five personality traits are significant predictors of relationship satisfaction.
Individual trait levels: The lower a partner's neuroticism (the more emotionally stable they are) and the higher their agreeableness, conscientiousness, and extraversion, the higher one's own relationship satisfaction tends to be. In other words, a clear personality profile of a "good partner" exists.
Couple similarity: Note that what Malouff et al. (2010) examined was the link between one partner's trait levels and the other partner's satisfaction, not the effect of similarity between partners. As for similarity itself, meta-analytic evidence indicates that in existing relationships it is perceived similarity (feeling alike) rather than actual similarity that predicts attraction (Montoya et al., 2008); see the article on similarity vs complementarity for details.
Limited role of complementarity: For extraversion, a combination where "one is somewhat higher" may sometimes be optimal rather than perfect matching. That said, there is no consistent verdict on whether similarity or complementarity works better, and for the remaining four factors being alike is no guarantee of a good match.
This site's compatibility assessment is a tool that quantifies this "personality trait compatibility."
External Stress and Joint Coping
Bodenmann's (2005) Stress-Divorce Model explains the mechanism by which external stressors (financial difficulties, work pressure, health problems, childcare burden) reduce relationship satisfaction.
What matters is not the stress itself but the quality of "dyadic coping" - jointly managing stress. Couples who can recognize their partner's stress and provide both emotional support ("That must have been tough") and practical support ("I'll cook tonight") can maintain relationship satisfaction even under high stress.
Bodenmann et al. (2006) reported that couples with high dyadic coping skills had higher relationship satisfaction after five years and lower separation rates.
In relation to the Big Five, people high in conscientiousness tend to provide practical support more readily, while those high in agreeableness tend to provide emotional support more easily. People high in neuroticism tend to be overwhelmed by their own stress and often fall short in supporting their partner.
Commitment and Investment
Rusbult's (1983) Investment Model demonstrated that commitment to a relationship is determined by three factors: (1) satisfaction (Am I satisfied with this relationship?), (2) quality of alternatives (Are there better options available?), and (3) investment size (How much have I invested in this relationship?).
Le & Agnew's (2003) meta-analysis confirmed that commitment is a powerful predictor of relationship persistence. In other words, the strength of the will to "continue this relationship" most powerfully predicts whether the relationship actually endures.
Commitment is also related to personality traits. People high in conscientiousness tend strongly to maintain relationships once committed, adopting a "let's overcome this" attitude when facing difficulties. Conversely, people extremely high in openness may find that curiosity about new possibilities elevates their evaluation of "quality of alternatives," potentially destabilizing commitment.
Sexual Satisfaction
McNulty, Wenner & Fisher's (2016) longitudinal study demonstrated that sexual satisfaction is an independent predictor of relationship satisfaction. The strength of that association is reported to be moderate.
An important finding is that sexual satisfaction depends more on "quality" and "alignment" than on "frequency." When there are large discrepancies between partners in the frequency or content of sexual desire, this leads to dissatisfaction with the relationship as a whole.
In relation to the Big Five, people high in openness are proactive about sexual exploration, and those high in extraversion are open about sexual communication. People high in neuroticism tend to feel anxiety even in sexual situations, and performance anxiety can reduce sexual satisfaction.
While this site does not directly assess sexual satisfaction, Big Five similarity (particularly in openness and extraversion) can be considered an indirect indicator of sexual compatibility.
An Integrated Perspective - How the Factors Overlap
Taken together, the research reviewed above reveals that relationship satisfaction is the composite result of the following factors.
Factors that cannot be changed: Personality traits (can change gradually), attachment style (takes time to change), age difference (fixed). These set the relationship's baseline as "initial conditions."
Factors that can be changed: Communication skills (learnable), joint coping ability (trainable), commitment (a volitional choice), everyday positive behaviors (can become habitual). These update relationship quality daily as "processes."
This site's compatibility assessment evaluates part of the "unchangeable factors" (personality trait compatibility). A high score means "a good starting point," but relationships do not automatically succeed without effort on the "changeable factors."
Conversely, even with a low score, it is entirely possible to build a highly satisfying relationship by consciously improving the "changeable factors." What research consistently shows is that "daily behavioral choices" have greater influence on long-term relationship quality than "personality compatibility." A compatibility assessment is a starting point, not a destination.