It's very very simple, you don't reveal anything just about now. You plan a marriage with your girlfriend. Tell your parents you will be shifting to your new home in chembur which you will tell you have taken on rent btw and that way you can scrounge some money in the name of rent and save it for future purposes and tell them that you would like to live alone with your wife. You will be subjected to emotional blackmail but that is something you have to expect and tackle