Court needs proof. First collect proofs and then you can file police complaint for outraging modesty.
I have not understood what is statuses and instagram post. Elaborate it. You said he using words such as Good for nothing, cheating wife, how he used, whether by telephone, emails, or which mode. You can file police complaint under Sec. 509 of I.P.C. The police will send a copy of your complaint to I.T. Department. You can also file defamation case under Criminal procedure and civil procedure. In civil case you will get damages. In criminal defamation, he will get punishment.
He cannot take legal action against you.
Once you clarify my above doubts, I can tell you where you have to file the cases in India or Dubai. I am extracting the relavant portion of Sec. 509 of IPC for your reference. It is better to contact me through Kaanoon.com. Are you a citizen of India or Dubai.
Section 509. Word, gesture or act intended to insult the modesty of a woman
Whoever, intending to insult the modesty of any woman, utters any word, makes any sound or gesture, or exhibits any object, intending that such word or sound shall be heard, of that such gesture or object shall be seen, by such woman, or intrudes upon the privacy of such woman, 1[shall be punished with simple imprisonment for a term which may extend to three years, and also with fine.]
CLASSIFICATION OF OFFENCE
Punishment—Simple imprisonment for 1 year, or fine, or both—Cognizable—Bailable—Triable by any Magistrate—Compoundable by the woman whom it was intended to insult or whose privacy was intruded upon with the permission of the court.