Pre ejaculation and unhappy sexual life.

Respected sir, I am working in banking sector and got married 6 months ago . right now I am residing along with my wife. Our sex life is no good as much as a normal married couples.I feel my partner is not happy my sex drive and even  she is not satisfied. We love and  respect each other , that's why she never expressed her self about this.while doing love making I  ejaculate within 2-3 minutes,now a days I feel very embarrassed and uncomfortable infront of her.due to this I am not able to concentrate on my professional life ,even  I feel very tense. Recently we came to close and tried to physically intimate but was unhappy ending with mentally afraid from pre ejaculation. Now I cofused and  about my marriage life , whether this will improve or not. I request you to please suggest me and guide  balance diet and exercise ,so that I can overcome from this problem and able to make my wife happy physically and mentally.