well the alternative to lying would be that both partners know they can't stand each other but are remaining together for the sake of the children, I figure once you are at that point of remaining together for the sake of the children and nothing else probably both parties know the score.

What if your (ex) partner takes the children away with them? You can't be sure that they also consider staying together for the children to be the best course of action.

Obviosly you are trying to take something that is not yours.

Getting a five finger discount to get (unilaterally) open relationship at a cost of regular one.

What do you mean? I don't understand anything of what you are saying? What am I trying to take that isn't mine? (And why me, I am not the OP)?

What is a five finger discount?

Five finger discount is when you steal.

The condition of staying in good relations with your wife where she does not take the children and blast off is not having a romantic life on the side.

You understand this condition but try to get around it by lying. Not because it is unfair or impossible. Just because you want to have good things without paying for them.

So in your opinion, the punishment for having an affair should be to have one's children taken away from you? Or at least, you think it is an appropriate punishment. I don't think everybody would agree.