What if girl who slept with me with consent blackmails me to marry

Dear Sir, i and a girl had a relationship and intercourse. Actually the girl was married and seperated. I never ever promised her that i marry her, but i used to say many times that i wont marry even before having intercourse. But then she agreed and emotionally blackmailed me to have sex. Now, she is complaining against me in police station that i cheated her by promising her to get marry. What should i do now? I am Backward Class and she is Scheduled Caste.