Notice period

I have been working in the organization for past two years. And I got married two months back. My wife is working at onsite, so i plan to move to my wife work location and then searching for job there. I got a dependent VISA and its validity only 4 months. Due to the separation of us, our both family also not happy, even I could not live alone. So I have sent the resignation letter to my organization to relieve me by giving one month notice period, but organization not accept that. Yes I agreed that terms and condition where termination clause "your services shall be terminable by giving three (3) months’ notice or three (3) months’ basic pay in lieu thereof on either side at the sole discretion of management". Another point "while on a project at customer’s site you be will required to give a minimum of 60 days notice period. I requested to relieve me on by accepting 3 months basic pay, They did not agree since am working at customer project. Then am requesting to give minimum 60 days as per policy. For that also they did not agree. So i continued to work by accepting the situation. Now its almost one month over but i could not work effectively by thinking my personal life. Again I requesting the HR, but they did not agree and forced me to work for 90 days. what should i do now? can i write a final mail as am not willing to serve notice period and release my relieving and experience letter after 90 days of my resignation date?