Getting a five finger discount to get (unilaterally) open relationship at a cost of regular one.
What is a five finger discount?
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.
There are a lot of ways to breach a "contract" that is marriage, including a voluntary termination. However, being unfaithful is a good way to ruin your marriage, so if it means things to you please don't cheat your wife, unless explicitly being on different terms (and even then...).
This one is totally reasonable. It does not grant you any protection for the other cases, though.