Romantic infidelity is not necessarily immoral.

You said - You have ignored both my presented argument and the working definition of moral behavior. We are assuming that an action is moral if it meets the criteria presented in round one. I never ignored your arguments. You said that any moral good does not cause harm. So I replied – people spend time and money in relationships. And seriousrelationships are like investments. Some people expect something out of iteventually; like marriage or living together. But you can’t marry two people. You can only marry one. So here’s how it goes down - One person is denied a fruitful outcome despite the time and moneythey put into the relationship. Savings all gone! Money on dates, vacations, andgifts all for waste!!! Cheating is unfair since one is making a full investment but theother is just taking advantage. You put 100%, but the other puts only 10%.Applies to money and sex!!! Time is precious! A girl spent her 20s and 30s on a cheater. Shewakes up, she’s 40 and no one wants her!!! All of these cause HARM. In a similar fashion, when you invest in a bank and the bank tells you lies andtakes away your money, you are obviously harmed regardless of whether you are awareof it or not. Your definition of what is morally good is irrelevant. You already lost this debate because you failed to make a similar ad-hoc definition for what constitutes harm. There many kinds of harm and its obviously not limited to feelings. You said - It is possible to love two people equally without loving one less than the other. Parents with multiple children love each child equally. Children love both of their parents equally. People love both of their eyes equally. Love most certainly can be divided. Commitment is different since it cannot be divided without being diminished. But the point is still flawed. As long as the other person is ignorant of the infidelity, she will not be upset. I never talked about love. I was talking about time and money. Think about it this way – you paid a whore a thousand bucks. She handcuffed you in bed, and tells you to wait while she undress in the bathroom. But she bailed out, and you are unaware. You may not be upset but unknown to you, you were already conned. And that is some major harm! You said - Think of it this way. If a doctor said you have cancer, would you be upset? Probably.But what if he was lying and you didn't know? Would you still be upset? Yes, because you would think you have cancer. Whether you actually have cancer is irrelevant. It only matter whether you believe you have cancer. Harm is not about being upset. In your example, the doctor lied to a patient. Because of this lie, the patient is now making decisions that affects not only his life but also of others. So instead of spending his money on prostitutes, bucket lists and everything to make his short life worthwhile, he spends them for more check-ups with the lame a$$ doctor. Double major harm! You said - What if both relationships are exactly where all parties want them to be? You were talking about infidelity (covert) in general. So let’s talk about relationships in general. And in many relationships, some people want to go to the next level. Cheaters can’t bring things to the next level so what do you say to the girl who wasted her 20’s and 30’s on him, her virginity and all her savings? You said infidelity makes at least one person better off. The cheater can be better off due to his romantic involvement with two people rather than only one person. In addition, you said - Honest disclosure doesn't necessarily bring happiness. If the cheater is honest, he could lose both partners. If he lies, he may be able to keep both, at least until he can end one relationship on his own terms. You confused well-being with pleasure. Your cheater is better off in terms of pleasure but I said – his conscious is not clear and he has to spend more money on two instead of one. His moral and financial well-being are in wreck! In conclusion, you don’t satisfy your own definition of what is morally good despite given the advantage of having to define it arbitrarily.