The Investment Model of Commitment: Why People Stay (and Why They Leave)

What determines commitment in a relationship and how can you strengthen it?

Caryl Rusbult’s Investment Model proposes that commitment is driven by three factors: satisfaction (how good the relationship feels), quality of alternatives (how appealing life outside the relationship seems), and investment size (what you’ve put into it that would be lost on leaving). All three are modifiable — and understanding which is weakest gives a precise target for strengthening commitment. The model has extensive empirical support across diverse relationship types and cultures.

Most people think about relationship commitment as a feeling. Rusbult’s Investment Model reframes it as the output of three inputs — how good the relationship is, how good the alternatives look, and how much is already invested. This reframe is practically powerful: it tells you exactly what to work on when commitment is eroding, and it explains why satisfied people sometimes leave (high alternatives) and why dissatisfied people sometimes stay (high investment). Below are practices derived from each model component.

Practices

Satisfaction audit: tracking what is actually good

Regularly inventory what genuinely works in the relationship — not as gratitude practice, but as an honest baseline.

Understanding and managing the lure of alternatives

Recognize when comparison to alternatives is inflating their apparent quality — and how to recalibrate.

Making your investments visible to both partners

Name and acknowledge the shared investments in the relationship — children, history, shared projects — to both parties.

Accommodation: inhibiting destructive responses to partner provocation

When your partner does something hurtful or irritating, practice responding constructively rather than in kind.

Willingness to sacrifice: building relationship-oriented decision-making

Practice making at least one weekly decision that prioritizes the relationship over personal short-term convenience.

Pro-relationship maintenance behaviors

Actively do things that maintain and strengthen the relationship, rather than expecting it to run itself.

Practice this with IX Coach

Reading about a practice changes nothing on its own. IX Coach turns these into a guided, adaptive routine — discerning where you are in real time and walking the practice with you, session after session.

Practice this with IX Coach

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