1. Change your passwords. All of them. Now.
2. Do not post on FaceBook (or Instagram or…) about your ex or your financial good fortune (exotic vacation, new car, etc.) or your new booty call buddy.
3. Don’t access your former friend’s e-mail, even if the password you have still works. Besides being illegal and wrong and not creating evidence you can use in court, you might not like what you see.