The goal of psychology should not be to maintain happiness; rather it should be to make human beings aware of their own emotional trends so that they may choose their actions in ways that are beneficial to them.
I absolutely agree with you that emotions serve an important purpose in telling us about what we must need, what is wrong with relationships, with the world.
The goal is moving towards the wants rather than shoulds.
Its about taking the risk of disappointing others or dealing with confrontation.
However a cheating spouse does not deserve retaliation by the spouse that was cheated on ... I know that it would be beneficial to me to begin to use this method, but how does one go from spending years accumulating lists of disappointments and ignored accomplishments to living in the present?
I can't even wrap my head around starting a day without any expectations.
The way out of this mental dance is focusing on wants – heart, gut-based rather than head based. Expectations are a red flag that shoulds are the probable drivers. A big expectation built into marriage IS fidelity, otherwise what's the purpose of marriage?
I don't think that analyzing how we feel means that should tamp our emotions down and be nice.
Rather we look at our emotions as information rather than must spraying them around the room and channel for change.
He wants the victim to convince himself that he/she would be happier if he/she just let things go, let things pass.
And from the evolutionary psychology point of view, I would even go so far as to say that emotions exist because they were productive / beneficial to the groups of human beings that had them.