ed problem... please help

Hello doctor, I'm 32 yrs old married man living in India. My problem is that my penis never gets hard. During intercourse I need to push it with the support of my hand to insert. Even when it gets hard for sometime, I feel like coming. When I stop to control, it becomes soft again very soon. Sometimes it gets soft in 2- 3 minutes only, due to which I feel very frustrated. I'm never able to satisfy my wife. The size of my penis is around 3-4 inches. The real problem is incomplete erection and inability to hold it. When i lie down on bed it is never hard and upward so that it can go inside. Please help. I also had a habit to masturbate. But now from past 2-3 m months I try to control it. Now I try to masturbate weekly and often do it without ejaculating. I have tried many ayurvedic medicines but never took homeopathic or allopathic medicine for this. Otherwise I'm physically absolutely fit and bmi is also normal. I'm cheerful person with no bad habits. Please help me to get over with this problem. I also want to make my wife happy and satisfied.