(2) Mental Insanity - three year waiting period and you are responsible for their support for the rest of their life (very bad option)
If you are thinking of a Divorce from Bed & Board (which is a judicial separation but not a divorce), then fault can be a factor and there is no statute of limitations. However, if you condoned the activity (reconciled and forgave it), that could be a bar to the adultery as a fault basis for divorce from bed and board.
Talk to an attorney!
Information posted for educational purposes only. No attorney client relationship created.