He is. He's... he's gone back home too and I really missed him. I am never taking him for granted either.
I can't even imagine what I would do with another version of me.
It didn't surprise me in the slightest. I have never seen a love like he and Dean have, and I get the not wanting to live without Dean part. I've had to live without Jess for years. If I was immortal I doubt I would feel differently than Cas.