The law of attraction comes down to two opposites that attract each other, this means that two types of people end up together because of personalities, interests , or even habits that equalises them as a partner together...
The Kind and Queen is a very popular example of this, the king all high and mighty needs someone by his side to help him rule his kingdom, and to make rational decisions in every aspect of his kingdom, but as much as the king needs his queen she needs him, to provide security and love, she needs him to need her before she can be of any help.