Friend accussed of sleeping with someones husband...

I've been best friends with a lady for 10 years and recently she told me she was having flashes of a memory of me sleeping with her husband. It never happened... She claims that when she lays down to sleep this memory comes flooding to her and she can't sleep. I'm a gay man and her husband is not in any way shape or form. When I talked to her and told her it didn't happen she told me it must have and she was going to confront her husband that night. I live in california and they live in Michigan I moved one year before this conversation came up. So I called her three times since then and she wont talk about it, but our friendship has changed completely. How do I get our old freindship back?