1. you can file FIR agains that person for the offence of adultery punishable under section 497 IPC.
2. no need to make your wife as accused because adultery is punishable against the man only. woman cannot be prosecuted however sex was committed with her consent.
3. divorce may be granted on the ground of adultery but it is your prerogative and you can choose to live with your wife. wife cannot get divorce on the ground of her adultery.