Contrary to evolutionary psychology's emphasis on matching 'mate value' (e.g., a 7 with a 7), research shows that mismatched couples (e.g., an 8 with a 5 in attractiveness) are no more likely to break up, be unhappy, or cheat. The initial perceived value difference does not predict long-term relationship success.

Relationship satisfaction can be improved with small cognitive shifts called "love hacks." These involve changing one's internal narrative rather than external realities, such as adopting a "growth mindset" about compatibility or reinterpreting a partner's negative behavior more charitably (e.g., as situational rather than characterological).

Dating algorithms that match users on objective similarities are largely ineffective. Relationship success is better predicted by *perceived* similarity—a cognitive bias where people who already like each other actively find and emphasize commonalities, a form of motivated reasoning.

A neuroimaging study found that when people feel their partner contributes to their "self-expansion" (making them feel more capable and positive about themselves), brain areas for assessing attractiveness are less active when they view alternative partners. A partner's praise can literally make others seem less appealing.

The optimal social dynamic for a relationship is having friends who celebrate your union and support you as a couple, but do not personally find your partner romantically appealing. This provides crucial validation without introducing the risk of competition or poaching.

The concept of a universal "mating market" is flawed because attractiveness is highly subjective. As people get to know each other, their agreement on who is desirable drops to a mere 53%, barely better than chance. One person's '10' is unlikely to be someone else's.

To maintain relationship stability, people in committed relationships unconsciously deploy a 'pro-relationship bias.' They automatically perceive attractive alternative partners as less appealing than they actually are. This psychological defense mechanism downgrades temptations and helps insulate the relationship from outside threats.

The idea of a universal attractiveness scale (e.g., '10s' vs. '2s') only applies to initial encounters with strangers. As people get to know each other over time, their opinions on who is attractive diverge significantly. This allows individuals to find partners they personally rate as a '10', even if others don't agree.

Studies show that when a person in a relationship has a sexual fantasy about someone else, it can increase desire for both that person and their current partner. This "rebound" effect suggests external attraction can temporarily refuel in-relationship desire, though acting on it is risky.