Managing Expectations - in a marriage

Someone once told me - Marriage is not about having any (more) expectations. It's about managing expectations - manage your own expectations of your partner.

I stubbornly turned a deaf ear to that advice. And now I think it is true.

A girlfriend (a fellow Libran) wrote : "And I don't think fate is destiny, it's in our own hands. I don't own people and people don't own me. Marriage can have many phrase, it's just whether I want to step out."

Clearly, not only has she reached the stage where she can manage her own expectations; she has come to a point where she no longer let her heart rules her head.

I wonder, at what point does one realise that she has to manage her expectations. Isn't managing expectations the point where you no longer expect the other to do anymore things for you because you know it didn't happen, it's not happening now and it will never happen? And what happens after one learns how to manage expectations?