I have had the same problem, but over time and as I fell in love with my partner and our sex life developed he became my main fantasy. Is there a specific sextual act in the porn that gets you off? Have you tried watching porn with your partner?
Secondly, making the sexual experience all about the ejaculation robs you of enjoying the act itself. Erotic touch, romantic feelings, taking time to make the act special can all help. If the only time you snog is drunk after the bar, or in-between American Idol and Bones, your lovemaking will not be of the same calaber as if you make time for it