This is about learning to say no in the first place. Once that opportunity is gone, you have already lost control of the relationship and either a hard debate or permanent separation awaits you in order to get your freedom back. This is about the "silent deals" made in relationships, because the optimistic sides presuppose their counterparts will think and approve and go along with any idea or action they initiate. Of course, nobody's the same out of the 7 billion plus inhabitants of this earth and this assumption turns out to be dead wrong when one's husband or fiancé or mother or teacher is not happy with what one has brought to the table, even if it actually merits appreciation. Then follow first disappointment, then conflicts, then anger and then inevitably separation. Although this wisdom has been spreading out quite recently, the best way to go is to talk every possibility, every common and uncommon likes through in the beginning so "no muss, no fuss" later.