Is there a way to divorce without a fight?
Now that I'm married and achieved the wish of my sim. How can I divorce without fighting my wife ?
In order to break up/divorce in the Sims 2, the couple's relationship needs to be pretty low. There is no happy way to do that. One way is to purposefully be mean and fight with your spouse. Another way is to have an affair and make sure your wife sees it. She'll be pissed and hurt and you can then break up with her.
I suppose not interacting with her for a while would also make your relationship drop and you'd eventually get the break up option, but that's just a guess.
Of course, if you just don't want to be married anymore, you can always just kill her, as Halfwarr suggested...