How beautifully you write about your lovely Teddy, Nick. He was indeed a very handsome cat and it's obvious you loved him hugely.
I so understand what you say about blaming yourself. I'm going through that now, after the recent loss of by beloved Bat Cat. What if I hadn't let her out that day? But it was a beautiful day, she loved the freedom of being outdoors, and as soon as I opened the door that morning she shot outside, eager to explore and do all those other mysterious cat things that they do, unseen my us.
My little Bat had a fabulous life for a cat, as did your Teddy. They had more fun and affection in their short lives that many unfortunate animals ever get. I'm sure they wouldn't want us to be too sad that they're no longer with us, but to smile at the happy memories we'll keep forever.
Wishing you a happy and peaceful Christmas.