Erection problem. Or urologist.

Dear sir, I am 33 year old healthy men. My height is 5 10 and weight 78 Kg. I don t have any bad habits( like -drinking, smoking, chewing tambaaku etc.).I got married in 2016. Sir since mid of 2015 I have facing problem of low sex drive and maintaining an erection longer(more than 10-15 second). Due to this problem I feel sorry for my wife and avoid to get cozy with him. Sir I never indulge in a relationship and never had sex. I have feel excited sometimes when seeing a beautiful girl and allways during lovemaking with my wife. Also I got hard erection sometimes at morning after wakeup. Here I want to mansioned that I have bad habit of watching adult content online since 7-8 years. I went to gym trice in week since 2013. Sir can you tell me what is my problem and for treatment of my problem whoem should I consult - sexologist or urologist. Thanks.