I Am Suffering From Sex Problem From Last 12-14 Years

i am suffering from sex problem from last 12-14 years . i am 33 years married and having 2 daughter . from the begging of marriage i never enjoy the sex. in my child hood i start masturbation and when my semen comes out i hold my penis tightly . after few months my semen stay inside, i enjoyed it but i stop enjoy it .i took lot of medicine but improvment is very less. can you advise me something