I realise now what those promo pics of Ianto were.
I know they were meant to cover the fact, prior to the showing, that Ianto wasn't going to be there all the way through, but now we see that they are just another lie to add to all the lies that made up Ianto Jones.

And you're right again. I probably could have come to accept the death of Ianto Jones, even death by lamest of plot devices. What makes it impossible for me to accept his death though is that they turned it into an ugly, festering wound. One that feeds on itself and won't get better.
I could (eventually) live with his death, but I cannot live with the fact that before he died they went to lengths to twist their relationship into something sad and (more) dysfunctional and reduce him to a needy, unlikeable queer woobie -- and then they continued to destroy his character and make him dirty after he died. The Debenhams thing was a shock when it first happened, and now it just continues to fester.
It's the over-riding need to make Ianto Jones dirty that I just can't live with.