In a relationship, the power lies with the one who give less, or love less. One has got the upper-hand power over the other. What kind of relationship is it when there exists such an inequality? It seems like a master-slave dynamics, which is perfectly fine to me, if you are talking about role-playing kinky sick (depends on who you talk to) stuff in bed.
In love and as in life, all should be equal.
In bed, that would be a different story.