According to Hindu Marriage Act, 1955, which deals with the laws related to marriages and divorces for Hindus, bigamy is not allowed. If there is a second marriage when the first one was subsisting and no divorce was given to the first spouse, then the second marriage is void ab intio, i.e., void from the beginning. Since in this case, the boy already had a wife and child and had not given divorce, his marriage with the girl in a temple is void.
Secondly, for alleging kidnapping, the girl should be less than 18 years of age and should be forcefully taken away from or lawful guardian or enticed or allured. However, it has been held in the landmark case of S. Varadrajan v. State of Madras
that if the girl had consented to being taken away, it would not be considered kidnapping. Hence if the girl had gone with the boy on her own volition by knowing the impacts of her act, you cannot file a FIR for kidnapping. However, it will amount to kidnapping if you can show that she was forced or enticed by conveying or indicating an encouraging suggestion
, the boy will be charged under Section 261 of the Indian Penal Code.
Thirdly, if the Police does not file the FIR, you can send a written complaint, by Post to the Superintendent of Police or the Commissioner of Police(in Metropolitan areas). Even after that if no action is taken then you can send an application to the Judicial Magistrate or Metropolitan Magistrate thereby requesting that Police should register FIR, investigate the case, file charge sheet or report. 
In some marriages only the husband or the wife can appear before the Court to terminate the wedding. In the present case this is a void marriage and in the case of Smt. Lajya Devi vs Smt. Kamla Devi 
it has been held that a third party can also appear before the Court to file a case to terminate the wedding if it can be shown that the third party has an interest, a civil suit for declaring the marriage void, can be filed. This means that in the present case, you being the third party must show your interest or benefit in the situation and can then file a suit requesting the Court to declare that the wedding is void.
AIR 1965 SC 942
Researcher - Shreya Mishra