Okay...I admit ignorance.
Has it been proven there was a sexual relationship? If so, I missed it.
I didn't say it was sexual but I am neither naive nor a child. Any thirteen year "friendship", if that's the term that you prefer, that a married man has with a single woman(who is not a co-worker) that involves an exchange of cash and that the married man conceals from his wife simply stinks.
You may draw your own conclusions - I have mine.