Case ipc 500 for having chat with a friend

A case is filed against my friend whom I have only met online, never physically. And I have been summoned under ipc 500 due to the fact that I have chatted with my friend after her marriage on social networking website and is romantic in nature. Thw message can be read by anyone on social website. Is it a valid case for defamation by the husband of my friend against me?? The message on social networking site was a personal message not a comment of post written publically.