IAAL is correct.
Besides, even if you could, would you want to give her the satisfaction of knowing she ticked you off?
Also you should know that the fact that there is another woman won't help you secure more property in the divorce -- because Indiana is a no-fault state. That means that you merely have to cite that there has been an irretrievable breakdown, not WHY.
The only time that kind of thing is useful is in a custody battle -- and you could use it to show he was doing outrageous things with her in front of the kids.
Otherwise, the court doesn't care about the adultery issue.
Hope this helps.