My ex-girlfriend accused me of being nice for when there is no involved?

I have been friends with my ex-girlfriend for the past 2 years. It has been a purely platonic relationship, no . We are great friends. 3 weeks ago, we had a big fight and she accused me of being nice to her for . There is no . Why would she lash out at me like that? We have not talked since, when we would speak every day. I am totally confused.