Divorce adultery

you can file a case against her. 

send notice to her and her lover.

after that file a case

HOW YOU RECORDED CONVERSATION

either break her head or go for MCD.  Only two options. Proving adultery is useless.  Either be ready to break her head and go to jail or roam to court endlessly or break your own head about having such wife.

Best option is go for MCD.

The evidence at UR disposal is not enough, unless U catch them red handed. May be Mr.Gyan Prakash is right

SHE CAN ALSO SUE FOR INTERFERING IN HER PRIVATE LIFE AS YOU HAVE INSTALLED APP IN HER MOBILE PHONE SECRETLY. ANYWAY, YOU WON'T SUCCEED IN TAKING DIVORCE ONLY ON THIS GROUND/ PROOF

If what UR saying is really correct, make efforts to catch them redhanded.Gather some more authentic proofs  to proceed further.U can never prove a lady for her adultery, go after her boy friend.

Even if u have recordings....this will take years to prove that its her voice....and u havent done any changes in the recordings... by the time, you get the divorce...you will old and not even willing to live your life...happily. 

Hence, either....put pressure on her via some common source OR pur pressure on her boy friend to get married to her.... then she would be eager to divorce you. If they having a time pass affair, then you are screwed........ as then she wont agree to give you divorce....!!! and you will be wasting years getting it.......

Just phone call recordings will not give credits. She could counter by saying that you suspect her fidelity. Don't waste your time on running in court lobbies.

As observed by many above and opined accordingly, it is  better to go for MCD instead of filing a divorce case on that ground which will become tough or you to prove your allegations.