Maintaince petition from my wife u/c 125 crpc

I shantha Kumar aged about 63 years old retired state Govt. employee drawing pension of Rs.15,000- I had extra relationship with my collegue she was widow and we are living togther for the last 18 years. After with the mutual consent we departed from each other. I never neglected my wife I used go every month to pay Rs.3000- and see my 2 sons. When retired from service I went to my wife to live with family and paying Rs.5000- for 3 years. During this period my sons started quarell almost every day saying that you have not done own house for us, you are not with us for 18 years why you came go back I never called you come back So I left the house now I living alone with rented house.Now wife petitioned against me for maintenance of Rs 10,000- PM u/s 125 crpc. I received notice from 1V principal Judge Family Court Bangalore summoned me attened on [deleted]. I am suffering from High BP, Diabetic awith neurological problems for my treatment monthly expenditure comes to 3,500- besides that Rent, electricity, water Rs,7,500-and for Food Rs.3,500- Please guide me how can I Maintenence to my wife out of pension. She have 2 earning sons.