I never bought into the "broken" meme. He's done worse and he lost more. Sp no, not "grieving" either, certainly not for one temporary individual in his life, if anything for the one he left behind, and possibly for the chain of events starting with the Doctor's abandonment. That is the tragedy of his life; not any individual "relationship."

And if he's looking for redemption, it's still going to bring him back to Torchwood and eventually Gwen either in the bonded friendship/UST mode or to resolve the unexplained, unexplored love that RTD alluded to.

The fact that our last image of Jack is smiling and handsome, doesn't really lead to a whole gut-wrenching, soul-searching thing, although how much would the J/I shippers hate it if that happened...and it was Gwen he looked to for help?