I wrote this prior to the broadcast of Children of Earth as a personal fanon bulwark against what I was afraid might happen. It didn't and since then I've been holding onto this, not sure whether to post or not. Then I saw This Post by alba17 with a drabble that deals with the same topic, and I felt the need to get my take out there. I'm still not sure if I'm going to cross-post and I'm open to concrit, although please keep in mind the point at which it was written and the pre-CoE hype that inspired it.
Title: Revenge Scheme
Pairing: J/I with hints of J/G
Warnings/Notes: See above. Thanks to beta_goddess for the look-over and the hand-holding.
Jack felt the warmth of Gwen’s approval for his compassion toward Ianto. In reality, he was making plans.
What Ianto had feigned to save Lisa would become real and what Jack might once have felt would become a lie. He could adopt a mask of monogamy or play at domesticity if necessary. In the end, Ianto would be absolutely convinced of Jack’s love.
Gwen might make an excellent instrument for the final betrayal, but the who was relatively unimportant, only the end result; Ianto’s suffering when the truth was revealed.
No one conned Jack Harkness and got away with it.