A relationship is comprised of a variety of elements. Individually, they can be found in a lot of our platonic relationships, but together they create the synthesis of a good relationship. What are these Elements and how do they contribute to bringing and keeping a relationship together?
Without compatibility in each of these elements, a relationship is doomed to failure. It is important to note that compatibility in all these elements does not necessarily have to be found and satisfied by this one person. Compatibility is in the form of similar views and perspectives on each element.
Physical: Of all the elements of a relationship, Physical compatibility is the most important. This can include sexual compatibility, but for the most part includes appearance, and the natural attraction that creates desire. No relationship can survive without physical compatibility.
Emotional: If physical compatibility can draw and bring two people together, emotional compatibility can keep things running smoothly. While it is beneficial for one partner to rely on their partner for emotional support, such is not always strictly necessary. Each person requires a different level of emotional support, and so long as we receive the necessary amount of emotional support from someone, be it a friend or relative, it can still work out.
Intellectual: Intellectual compatibility is when like-minded people are paired together. Does one partner require a greater amount of intellectual stimulation from their partner? Do they receive such stimulation elsewhere?
Spiritual: Spiritual compatibility is when both parties either share a similar religious or spiritual outlook, or neither partner creates obligations on the other to share their beliefs.
If I were to describe my ideal partner based on the level of compatibility I require, I would not want my partner to depend on me for emotional support. I would want her to have a support network she can rely upon. I do expect and desire to have a high level of intellectual compatibility. I have a desire to discuss and debate various topics, and would hope that she would have a similar interest in intellectual topics. I am not particularly spiritual, nor desire to have a partner who finds her faith in organized religion. I am not strictly opposed to religion, but I would not want my ideal partner to pressure me into participating in any religious activities. It is likewise natural for me to be attracted to my partner, and would expect that she would likewise share in the attraction.
When the elements of compatibility are in balance, and neither partner is putting undue demands or ultimatums on the other, you have the foundation for a successful relationship.