[fnordfnordfnord]

I think I was quite clear as to why a marital relationship is a private matter.

I think we can agree that in society there are many different moral systems. Now I will use the words "good" and "bad" with the stipulation that these words have no inherent meaning, but instead only have the meaning that we apply to them from within our own personal moral system. You can compare another moral system to your own, and decide that it is "better" or "worse" but you cannot make an objective determination. Now, you can decide that your morality where adultery should be prohibited/prevented/punished is better for your purposes than mine where adultery is none of the government's business, but that is just your personal preference. The problem is that this may never end and there is always another fellow who is more moral than you or I or both of us, and whose morality tells him that shoes are immoral or that red-haired people are witches or something like that; and this fellow wants the government to segregate the witches for the protection of the good moral folks, and also prevent everyone from wearing shoes, even firemen. So, we have to compromise on our morality and find a set of common rules upon which most of us can agree and which will protect people from serious harm even if it allows for some behavior that makes some of us uncomfortable.

Why do you think that two other peoples' marriage is some concern to you, or to society at large? And please, no references to vague concepts that we have no real definition of such as 'making the world a darker place'

>For me, that would be very nice indeed! Convincing moral arguments are very rare!

That's because morals are very personal, arbitrary, and often irrational.

[josinalvo]

Thank you for your reply.

No, I am not harmed when two people (Pa and Pb) are married, and Pa cheats on Pb. The reason I'd oppose AM is because it normalizes and helps the harmful behaviour of Pa towards Pb. I am quite sure that there is some marginal contribution of AM to the number of cheatings and broken marriages. I think we can objectively say that AM contributes to needless suffering. Do you agree?

[fnordfnordfnord]

We can agree that act(s) of marital infidelity cause people to suffer. Sites such as AM are not my favorite thing, but it is simply not my place or yours to tell other people how to manage their personal lives. I do not think that the existence of AM causes anyone to think that infidelity is okay who did not previously think that was the case, therefore, AM is not contributing to the moral decay of society. I'm not going to transfer the blame to the third party. AM did not force anyone to participate. There would still be marital infidelity if AM did not exist, and as you say, I expect their contribution to be marginal.