Most people would probably say that a successful marriage is based on unconditional loving. The truth is, however, that
people usually don’t marry because of unconditional loving; they marry for conditioned loving.  Conditions are presented
to each other, including that they love one another unconditionally, based upon conditions. They often demand that the other person fill that empty, lonely, insecure space inside of them, and the person simply doesn’t know how to do that. No one knows how to fill up anybody else regardless of all the romantic songs and movies. In fact, very few know how to fill themselves up.

– John-Roger
(From: Relationships: Love, Marriage and Spirit, p. 16)