1) file case of adultery against the boy . under section 497 of IPC . that boy knew your wife was married yet has tried to ruin your marriage and ruined your relationship with your wife . he instigated your wife to leave you and stayed together with her .
2) your wife obviously does not want to continue relationship with you . if you so desire you can file for divorce by mutual consent .
3) if your wife refuses divorce file for divorce on grounds of adultery , mental cruelty
4) gather evidence of her extra marital relationship with the boy
5) an adulterous wife is not entitled to any maintenance .