Jack coming home after the wedding to look at the picture of his wedding was such a wonderful add on at the end because for the most part, his behavior towards Gwen and her wedding was absolutely fine. But there were moments when his behavior seemed...uneven. Compare his behavior after Ryhs saves Gwen and Jack "sweeps her up" where he's playful and relieved and touchy feely but not really romantically so, compare that to his dance with Gwen where it clearly borders on the romantic. That moment seemed very uneven to me but put in context with the final scene with the picture of his wedding makes complete sense: he's not feeling romantic towards Gwen per say, it's more that he's remembering his wedding and what weddings mean and specifically what his wedding meant to him. He's remembering his feelings and what he tried to have probably knowing at the time that he couldn't have it.

The dance with Ianto was sweet. I'm curious if Ianto's father really was an expert tailor. It would explain his love of beautiful suits.

And it's probably needless to say but I'm really looking forward to Part 2. :-)