[He can't help thinking of her and Reid too (weird how sometimes that seems like it was only a few weeks ago, rather than over two decades) and how much happier she was once she finally accepted it was over and moved on.
On the other hand, she had someone amazing to move on to, someone she was - and still is - in love with. He's never found anyone like that here, and now, with no new people arriving, ever, he's not likely to either.
Which is, perhaps, why he always knew he'd end up gravitating back towards Ianto in the end. He just never, due to his shortsightedness, expected Ianto to refuse to have him back.
He shrugs a shoulder morosely.] He made it extremely clear it's never going to happen. He's got Spike, and Spike still dotes on him as if they're newlyweds. He doesn't need anyone else.