Her brother knows what she is and was searching for a bakra to pass on the liability !!! Dont ever give her a hint that you are planning for divorce!! Just be normal with her. Collect all evidences for her behaviours from now on, if you have not done yet. Involve a third person for mediation, some elder known to both of you or both families and sit and decide on a MCD !! dont worry about losing money. You can earn it by going onsite. Peace of mind is more important. File for MCD and plan to US. Dont run away from problems. Face them and settle!