As some have noted I chose to conclude Valerie. Whilst it would appear to be an awkward place to stop, frankly I couldn't see the story going realistically forward and there's only so many ways you can describe various sex acts and situations.
For the record, no, John never gets caught.
Jan never finds out.
Ginny never tells.
Essentially John is the perfect fantasy as a guy who gets to keep his cake and eat it.