[John may not know that he is the one to eventually raise Jamie's son. But he does know that Willie is Jamie's son, and he understands that Jamie will never be able to lay claim as such. Not without denying the boy the rest of his family. The title he was born to.

So no, Jamie may have sired the child, but he will not raise him. And apparently he was denied the right to raise this child as well. It is a predicament, he will give Jamie that.]

Jealous of the time he spent with her that you will never be able to make up for? Or jealous of the fact that she should love him more than you, when you have only just met?