I just got a call from a man that says his wife is cheating on him with my husband. He said he just wanted to let me know, because he felt it was only fair that i did. His wife says they've never met, but have been talking online for about 2 months...talking mostly about their marital problems ( I didn't know we had any ).

My husband denies this. He says he doesn't know what is going on with it. If this is true, should I consider it as cheating? Is talking to someone online cheating? I don't know what to think about it.