Here are four primary types of compatibility, and all of them are necessary for healthy love. However, the first three are subject to change, while the fourth type of compatibility is the one that truly cements relationships for the long haul — it is the eternal element that keeps couples together when their looks and interests change.

Physical Compatibility
Though it may sound superficial, physical compatibility — physical attraction to one another — is necessary for a relationship to take hold and be maintained. You need to be attracted to your partner, and certainly not be repulsed. Beauty is in the eyes of the beholder, and physical compatibility is clearly based on a subjective set of preferences. Nevertheless it is an important component in a relationship.

Emotional Compatibility
You can be attracted to someone physically, but if emotionally there is no connection, the relationship cannot endure. This happens very often: People look beautiful on paper or in real life, but when you meet and talk to them, you don’t feel anything — there is no “click”. Every healthy relationship needs a feeling of trust and commonality, as well as emotional nurturing.

Intellectual Compatibility
Intellectual compatibility is two people who respect each other’s intelligence. They share and are stimulated by each others ideas and/or shared intellectual interests. They value each other’s opinion and thoughts. They find each other’s conversation interesting.

Eternal Compatibility: The Shared Vision
Not to diminish the importance of the first three types of compatibility, there is a fourth element of compatibility which infuses and lifts a relationship to another dimension — and actually turns it into an eternal relationship.

It is called spiritual compatibility: Two people who share a vision and a mission — a vision that transcends each of their needs and the day to day changes of everyday life. They ask themselves: what transcendent vision do we share in how we would like to contribute to the greater good? What mark in the world do we want to make? What kind of home do we want build together? How do we want to raise our children, and how do we want them to shape the world they will grow up in? When people come into your environment, what kind of feeling do you want to give them? What legacy are you leaving?

In contrast to the first three compatibility types, which are all subject to change (due to age, changes in our needs and interests, maturity) this fourth one lasts a lifetime and more. No matter what changes a person goes through in life — physical, emotional, intellectual — a vision does not change. Your vision and mission can take on different shapes and forms. Your fundamental personality — your essence, your personal mission — does not change. You discover new ways of manifesting your mission in life, but your essential calling and your key talents don’t change. When two people find a partnership on that level then their relationship is able to evolve throughout life.