My husband had an affair for a year with an unmarried woman and I want to know if there is a way I can take her to court and press charges?

While some states still have adultry laws on the books, most have been found to be unconstitutional. ( state will not look behind close doors as to what a two people are doing in the bed room)

Have you filed for divorce ? And of course if you press charges on her , if even possible, he would have to be charged also, since he also had an affair.

Get your divorce and move on with your life, trying to get even and keeping hate in your heart will not ever do you any good.