Even if you file for divorce on the ground pf desertion after 2 years, you will have to prove it in the court. You will not get divorce on any ground straight way except MCD. The grounds you take before the court are to be ‘proved’. The instance of cheating you mentioned is not available to you as a ground as your marriage is now old one. Consult some local lawyer and brief him/her with all the facts in detail and see if the grounds of mental cruelty are made out. Betterway if your wife is not interested in coming to reside you then, convince her for MCD. Even if you file on other ground now, the petition can be converted into MCD if later on she agrees for it.