50/50? Really?

Why do people say that relationships should be 50/50? There is no such thing. There is always one person that gives more than the other. But the question is when does the person giving the 60 or plus % stop wanting to be the one giving the most? When do you get tired of giving so much and not getting what you expect in return? Why can't it be equal? Why can't we love equally? It just is not in the human nature of things; men like to be the pursuer, women like to be pursued, some women enjoy being the pursuer as well. Why the games? When will it all be put to rest and a couple can be together without the games and the bullshit? Why can't it just make sense? It hurts when you are the only person, or so you feel, putting the energy in the relationship to keep it together. When do you get tired of keeping it together?; when do you say, I want to give up, because it is just too much to always be trying to keep it together. When does being tired turn into giving up and walking away? The sands of time turn, but to what? to when? I don't know. I am just asking the questions. It just does not make sense to me at all. Why should one person always be giving more than another when it comes to love? Can't it be total requited love? When did that go away? Let me know.