Turns out there are lots of mistakes in the official site. And don't get me started on the dates. They can't even add. Math, anyone?
They never mentioned or even hinted at a possible relationship between the two characters in the show and they never really shared a real scene together (except the one where she killed him) so there's no point in discussing it only because that's in the official site. I wouldn't read into it.
And anyway, even if she had an affair with him, doesn't mean she loved/loves Jack any less. They were apart for 20 years. I'm pretty sure that Jack didn't became a priest after she left.
I could also say the same thing about the current status of the S/V relationship.