A combination of elements in a relationship can create a loving balance; thereby resulting in a relationship that thrives on mutual growth and harmony. Two well matched combinations are an Air-Fire relationship or and an Earth-Water relationship.
The element Air in a relationship provides ideas and dreams that Fire can act on and forge into reality. The element Water provides sensitivity and nurturing to the sometimes cold, reserved Earthly approach to matters, thereby laying the groundwork for future growth in the relationship.
At the same time remember in a Fire/Water relationship, balance can be achieved by realizing that Water can inject needed sensitivity and patience into the Fire sign. At the same time, Fire can add drive and the courage to act that can be sometimes lacking in the Water signs.
When two elements of the same type combine, harmony can be achieved when the needs and traits are the same for both. However, it hinders growth when both individuals may become too comfortable to a point that the needed spark for growth may be lacking.
In a Fire/Earth combination we find that fire’s initiative and drive can stimulate the sometimes laid back and reserved nature of Earth. At the same time, Earth’s practicality and discipline can be balanced to Fire’s sometimes quick to act ways. Ideally we should strive for a balance of the elements Earth/Water and Air/Fire.
The other combinations can also work as long as both partners respect the other's needs and unique traits that both bring to the relationship. And they must utilize each other's strengths to balance.