First, understand how this is advantageous to you. A no-fault divorce generally means that the marital estate is divided by equitable means. Equitable means fair, but not necessarily 50/50. See here for a good explanation:
Under New Jersey Statutes - Title 2 A - Chapters: 34-2, adultery
is grounds for a "fault" divorce. How is this different? If you prove a fault in your divorce, you are more likely to get (1) a division of property in your favor, and (2) alimony
amount. In other words, his fault may be weighed against him in the subjective decision-making power of the Court for purposes of property, assets, and post-divorce alimony support.
It is up to you whether you wish to (1) tell him you would use the evidence and have it be public when you file
and call his mistress to court as well as ask the court for a decision in your favor in terms of division of property, etc, unless he agrees to an uncontested divorce in your favor; or, simply agrees to a divorce - period - since I do not know what it is that you specifically seek; or (2) spring it on him when you file for divorce and mark "adultery" as a claimed fault.
The bad side to telling him before filing is that he would have ample time to work out a defense (he would, anyhow, after you file). On the other hand, you really do not know what will happen in Court if you try to prove the adultery. Ergo, it simply depends on how this plays out.
Nonetheless, I hope this has given you the information that you can use to make an informed decision.
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