Sick to my stomach. What does my friend mean?

A friend of mine says we need to talk because she's not the person, I think she is. Well I know she had an affair so it's not that. What else could you possibly do? The only two things that came to mind is murder or her being gay/bi. But I don't think either one of those are it. I guess I put her on a pedestal but I love/care about her for her imperfections. What does she mean by this? My stomach is in knots.