The actual phrase "I love you" hasn't been uttered, no. He does admit to loving his friends ("A Good Man Goes to War"), but the closest he ever comes is in "Doomsday" but he is cut off before he can. Without the actual phrase being used, however, his actions in various episodes have suggested him being in love. Examples include "The Girl in the Fireplace", the aforementioned "Doomsday", several of the River Song episodes (most notably "The Name of the Doctor") and it's also been implied that the Doctor (at least the Eleventh Doctor; whether this continues with the Twelfth remains to be seen) had feelings for Clara ("The Snowmen", "The Time of the Doctor"). While under the control of the chameleon arch and in his human John Smith persona, he was unambiguously shown to be in love with Joan Redfern to the point of imagining living out the rest of his days with her as a human ("Human Nature"/"The Family of Blood").