Relationship Blackmail by partner by sharing intimate images

Me and my gf was in relationship for past 5 years, i have sent money around 7-8 lakhs on gpay for her expenses in the past years since i was thinking to marry her, now it is all negative and she is having my nude photo and blackmailing to post it in social media by adding all of my friends, also she is having control of my instagram and email account and threatening to post it when i say i want to end this relationship and is saying that she will give false police complaint that i am cheating, what can i do now? please advise, i have been mentally harrased over this for the past 8 months i want to get rid of this. she threatens that if i give complaint to police about this nude photo, she will give complaint that i cheated her, what should i do now?