Legal Question in Family Law in India

you need to first divorce under hindu law and then marry under special marriage act.

A married man is not entitled to consider marrying again with some other girl. You may not be allowed to divorce your wife if she not committed any offence. Therefore, you better forget this girl and treat her like a sister. You should try to save your married life before your wife comes to know of your intentions. She may seek your criminal prosecution and you may suffer a jail term.