Unable to understand my real problem.

Hi, I'm a 35 year old married physically normal male. I look normal in appearance. But, I'm in a very bad state psychologically due to mainly, my marriage being bad. I don't feel emotionally connected to my wife and do not have any sexual attraction towards her, even though she's physically beautiful. But I've a huge sex drive and fantasize about many other women, even though they may or may not be beautiful. I never had a good sex life. Although I have controlled my carnal desires so far, I'm not sure how long I'll be able to do that. Also, for many years, I have been watching porn everyday and masturbating. I'm addicted to smoking and drink occasionally. Generally, I'm always in a frustrated state of mind and this affects almost everything that I do. Please help me with a recommendation on what kind of doctor I should visit to get treated so that I can come out of this and lead a normal and healthy life with dignity and self - respect.