You have admitted to the biggest mistake of your life. You got fooled by this girl about a FALSE ritual of marriage. Do you think that any family who is under deep sorrow having lost the head of the family to perform celebrations and marriage within a year. Rather it should be that no one should get married within a year. This is so lame of you to have succumbed to her pressure.
Her tactics worked wonders for her because now you are maintaining the girl, her mother and her sister. I don't feel strange that you are in this situation. It was bound to happen. And let me warn you, as soon as you think about leaving this girl, she would dump you in the garbage of cases like 498A, DV Act, Maintenance etc. because if you are gone, who would take care of her family.
Take steps with caution. It's very critical time. You are not the one who has to maintain whole family of bride. Only bride is your responsibility. Start gathering evidences which would show that she is only taking advantage of yours. Though it's enthical but I would suggest you to start fabricating evidences to show that your wife is creating problems in your life. Not allowing physical pleasure is also cruelity against the spouse and this makes a ground for divorce. See a good lawyer to get your case doctored.