I am 33 years old and till 4 months back I had never ejaculated in my life since I did not have any sexual intercourse or do masturbation but had nocturnal emissions twice or thrice in a week. Recently I got married and I started having intercourse. During intercourse initially I have a proper erection but once I insert my penis into the vagina, my penis starts to shrink and I am not able to have a proper intercourse and also I don't have a ejaculation. Also I started masturbating 4 months back and I am able to ejaculate properly within 5 to 20 minutes of starting to masturbate. In fact sometimes I start masturbating immediately after the ejaculation and I get a second ejaculation within 20 minutes. My doubt is if I am able to maintain a proper erection for 5 to 20 minutes during masturbation and maintain proper erection even for a second ejaculation, why am I not able to maintain erection during intercourse with my wife. Is it something psychological? Please help me as I am planning to have a child and since I am not able to ejaculate during sexual intercourse I am not able to have a child.