One way for a couple to think about their relationship is for each partner to say of it, "There is me, there is you, and there is us." It’s in the us where the couple gets to create the relationship, including what role sex will play.
In almost any couple’s sexual relationship, one partner has more desire than the other. If this partner’s desire isn't reciprocated by the other, it puts the partner in a weakened position, facing the possibility of rejection anytime he or she makes an overture for sex. Bert Hellinger, the founder of Family System Constellations, sees the balance of give and take as one of the fundamental needs of any relationship, and it is especially important in the sexual realm.