If there were any indication the Doctor even felt the slightest bit threatened by the prospect of Rose sharing a roof with Jack Harkness, he certainly didn't show it. He trusted the ex-Time Agent implicitly, even if the man did have an impressive knack for lacing sexual innuendo into even the most neutral of conversations at the most inopportune of times. Par for the course, as far as the Time Lord was concerned.
“Good! Because there's a small matter I'd very much like to speak with him about, specifically concerning the lovely little scenic town we all seem to have ended up in. Does it have a name?” he asked, reaching out a hand and wiggling his fingers at her in invitation. There was another topic of interest he'd very much like to get to the bottom of, one that only seemed to grow louder the closer he drew to that small town ahead.
For the moment, however, he kept the suspicion to himself. No need to cause a fuss if there weren't a fuss to be had, after all. He didn't need Rose thinking he'd finally gone off his nut, either.