I believe that Julie Gardner said that during one of the question-and-answer sessions at one of the cons where she attended. I'm not claiming certainty on that, but I believe a question was raised regarding Gwen, Owen, and Rhys and the reasoning given by Gardner was that Gwen turned to Owen because no one outside of Torchwood could understand or comfort her. I don't get it, but there is no point arguing with a Torchwood producer about why Gwen does anything.
Has anyone else seen the new SFX interview where RTD says that Torchwood is in fact over, but that the name is being kept for the reboot on Starz? At least it has been admitted now.