What Could Cause Sudden Erectile Dysfunction With Previously Normal Sexual Function?

Hi, i'm 28 years old ,5'7 weight 60 kgs , i'm recently married , until a month ago my sex life is good , my isnt staying with me , suddenly i tried to have to sex outside , i expreinced eryctile dysfunction, i approached physician. He suggested nano leo capsule , but my erection is not hard on seeing porn , i 'm tensed to try sex again.