I'm new on this and so don't know how to attached pictures to this. So, I guess I'll just point you all in the right direction if you are interested in confirmation of who the spy is. I know this was already leaked time ago, but it appears to still be a debate.
Nick said that he knew Jesse from college in Florida. I found what appears to be his picture. Nick Schiralle played in 1999 for U of Florida, same year as Jesse. Here is the link to his picture:
Next, Nick also said that his wife lived next door to them in Florida. I found a picture of a Jenny Deloach who also went to U of Florida, was a swimmer, which she confirmed on the show, and also attended in 1999. Take a look at her picture at this link and tell me if you think this is Jenny S.
Of course, this doesn't prove that she is married to Nick. But it does prove that they where in school the same year. And it explains what the 'S' stands for in Jenny's name (Schiralli).
Is this still debatable? I don't think so.