Possible adultery - What can I legally do?

Is it true that in the state of North Carolina, the only way to prove Adultery is by photographing them in the act? I have my husband on tape stating that he "cheated on every woman before" me and that he "almost wishes" that he would have "f'd" the other woman in front of my face because "at least then" it would have "been truthful". Is this not enough? I have no way to prove that they are living together, but when I asked him if they are, he smiled and said "that's none of your business". Since then, he has written me a "formal letter of demand" telling me to "cease and desist" and has put up black curtains in his house (I moved out after he threatened me). What can I do about this? I do not have a lot of money but I do feel that I have been wronged in this mess.