Interesting take on Jack and his emotions. I agree he's hurt Ianto in the past by not noticing small things. I think I've always just assumed that Jack is so busy simply...being...that he just doesn't ever stop and take stock of how he feels about Ianto.

I told someone else recently that Jack understands he's going to loose Ianto some day and that scares him but he's come to realize he's got too long to live to simply stop feeling and becoming attached. A lot of fic writers portray Jack and trying to avoid getting attached to anyone because he'll loose them. I believe Jack is heroic enough to become attached IN SPITE of all that. Perhaps only since the Year That Wasn't, but true all the same.

Oh, and I do believe that Ianto has replaced the Doctor in Jack's life as the person he strives to be a better man for.