Well, Jack has Andromeda (Rose and the Doctor's granddaughter) who is definitely his soulmate. I created her with him in mind to help make up for all the stuff I've put him through and she's pretty terrific and is utterly devoted to him. And he adores her.

Oh, well, I'm American so I always translate. Though I'm not sure England is on Kgs, I think they do pounds, too. But I figured the Doctor would have a scientific scale which would be in Kgs regardless. And Jack, being American sort of, would automatically convert it to what he was used to. Same way I always have Jack saying Mom instead of Mum. Just one of those things.