Unable to Enjoy sex life. To for advice.

I have been married for 2.5 yrs but am still a virgin. My relation with my wife is very good as we are close to each other and have been in love for 5yrs now. But some how our sexual life has not been like expected. The problem is clearly from my side as its me who's always been hesitant to discuss on this problem openly even with her. Its not that am not interested in sex, i have always liked forward for my first experience but post marriage some how everything changed in me. I still watch porn and get aroused and would want to get involved in sex with my wife but at the moment my mind doesn't cooperate. I wanted to visit a doctor for counseling but didn't know who's the right kind of doctor for this issue of mine. Please help me and suggest how do i go ahead or what could be my problem or whom do i go to for advice.