I want to divorce my wife and want to know alimony calculation

Respected Sir/ Madam, Let me first explain my matter in brief so you will get clear idea about what information or advice i seeking from you. Kindly bear with me please. Myself Mayur Khairnar 27 year old and i am Software Engineer living at Ahmedabad. I married in Nov 28 2014 in Nashik and it was pure arranged marriage. My wife's age is 22. Since i started my journey with my wife at my parents home and from the first week i noticed my wife was not adjusting with my family and always having complaining nature then i decided to stay separate and started living on rent near to my parents location. After relocating my wife's demands not satisfied and she used to complain about my family whenever i took her to my parents home once within a week. I stayed on rent for one and half year but because of my wife's complaining nature i used to stay frustrated all the time because she did not like to contact my family member at all. I left two of my jobs just because of her complaining nature. Her father is main villain of my story because he is damn or i can say over-possessive about her because whenever my immature wife used to say my family matters to him on call he then used to took her to his home and kept her for two or more months and returns her after verbal fights with me and my family. It happened 3 times to me within this 2 years. Just for the comfort of my wife i started living separately not only that i brought my own 2bhk home and also brought a own car just to make her happy and without any support i took a loans for it and it is all for my wife's comfort but my wife at the end always obeyed her father more than me. She likes to stay at her home for longer time period against my wish. My recent incidence is that her father came and took her to his home while she was pursuing 7th month of pregnancy. My wife again as per her nature complained about me and my family to his father besides she knows his nature. He then told my wife to not contact to me and my stupid wife stopped contacting with me for last four months and used to text me using facebook chat only and i have her messages in which she said her father threatened her to not contact me and not any other member is receiving my calls from her family. It is totally ridiculous to me yet i did bear all because i do care and respect my wife but you can see how her father is interfering my personal life and girl just taking advantage of it. Till delivery i accepted all the non-sense things like she not able to contact me because her father threatening her but matter gone more ridiculous when i got to know that her parents did not inform me or my family regarding her delivery and not even my wife informed that she given a birth to baby girl. I get to know it from one of my relatives after a 5 days late it is the height of cruelty. Even after the delivery my wife just texting me on facebook now tell me sir/madam which girl could talk with her husband in fb messages after delivery ?? Cant she send sms or call me ???? what rights her father have for doing all this stuff ??? I wants to talk with my wife and want to hear voice of my kid and my wife afraid of her parents ??? i literally frustrated and this frustration spoiling my personal as well as professional life. I took advice of my close friend's father who is advocate and as per his opinion i sent her and her father a legal notice stating all the above matter and asked them to revert back within a ten days and its 6th day today still there is no any reaction from their end and not my wife or any family member receiving my call and also not receiving calls from my parents. Apart from this matter i checked my wife's fb messages and i found she did a lot of flirts with guys while she was at her parent's home and i took a print out of all that messages in which she did bad chat with other guys in my absence. I also took a print out of all the fb messages in which she said that she wants a divorce with me and she will be agree for divorce at any point of time. I carefully took a print out and it contains messages with date and time. As i mentioned her father did same incidence with me 3 times before that is why last time when my wife was with me i written a letter in her handwriting that contains "If i did anything against my husband's will and obeyed my father and stay longer at my parent's home against my husband's will then in that case my husband is free to take any legal action on me and i wont request for single rupee or alimony or maintenance from my husband. I agree with what i have said all in this letter" and took her signature on that paper. I have that paper with me as well. I discussed all the matter in clear way and i hope it is clear to you and all i need is your suggestions or advice on my following questions: 1. I want to divorce my wife but alimony/maintenance could be refused based on her writing letter? 2. I have print outs of messages in which she stated that she wants a divorce. Does this proofs are fair enough to file divorce petition based on mutual consent ??? 3. I took Home Loan, Car Loan and Personal Loan all these deductions are debiting from my net salary. After deducting all these loan amount only 15000 remains in which i paying my mobile bills, credit card bills, petrol expenses and also giving some amount in my family. Hardly 5000 remains after deducting all expenses now please tell me if alimony is requested then how it would be calculated in this case please ? 4. Should i go for divorce or 498a against my wife and father-in-law ? Do we have a provision to file 498a if i am a husband ? 5. Is my proofs are fair enough to refuse alimony or maintenance ? Thank you for reading my whole matter and i hope you give me a clear advice as i am more frustrated now if you can put yourself in my situation. I need advice from you for which step i should follow. Thank you so much Sir/Madam.