Most spouses have invested enough time, energy and emotion in forming the relationship that they fear this. Some defecting spouses avoid the problem through denial, convincing themselves that a defection doesn't count if it is not discovered. In a James Thurber story I remember from childhood, a woman who could not bear a stupid story her husband told at parties finally retaliated by always telling one of her own. If you never wash a dish, my most effective answer may be to stop doing so myself. If it makes you sick to be surrounded by dirty dishes, you will end up pitching in.
Love is supposed to be unconditional and selfless, inviting the sucker's payoff.
She was shocked that I would link the two issues. Being in love is the first rush of strong emotion when the game is about to begun. At this point the only cooperation desired from the other is to be there. Being in love is effectively a relationship you have with yourself that is catalyzed by the presence, frequently dimly perceived, of another. It is possible, even quite likely, that you will fall in love with little or no knowledge of the other.