1) you can file police complaint against your ex wife under section 500 of IPC for having malinged your reputation by calling you cheater and uploading it on face book
2) you can also file suit for damages and claim compensation from your ex wife
3)66A.of IT act Punishment for sending offensive messages through communication service, etc.,
Any person who sends, by means of a computer resource or a communication device,—
(a) any information that is grossly offensive or has menacing character;
(b) any information which he knows to be false, but for the purpose of causing annoyance, inconvenience, danger, obstruction, insult, injury, criminal intimidation, enmity, hatred, or ill will, persistently by making use of such computer resource or a communication device,
(c) any electronic mail or electronic mail message for the purpose of causing annoyance or inconvenience or to deceive or to mislead the addressee or recipient about the origin of such messages
shall be punishable with imprisonment for a term which may extend to three years and with fine.