1. The girl is already married to you by marrying you following Hindu customs of marriage at the temple. So, for getting rid of you as her husband, she has to take a decree of divorce from the Court. Before that she can not remarry. Whispering is an acceptable evidence before the Court,
2. First of all you file the police complaint as suggested in my earlier post if you are serious about the matter. However, if they file any FIR, engage a lawyer and avail anticipatory bail. AB can be taken only after FIR is filed. The fees vary from place to place. In Kolkata, it should be over at Rs.30,000/-,
3.You will in no way be responsible for their harming themselves. Lodge the police complaint well in advance as suggested earlier.