You do realise that a sexual fantasy carries pretty much no legal weight whatsoever, don't you? On the other hand, proven consent (without evidence of coercion or lack of capacity) carries a heck of a lot of legal weight.
For example, let's say I fantasize daily about being fucked by <INSERT CELEBRITY HERE>, and I broadcast my fantasies publicly. If said celebrity then engages in non-consensual sex with me, they have committed rape.
If there is sufficient evidence that Mr Payne raped Ms Hughes, that's all that matters and should matter. Even if those e-mails are proven to be written by her (PS: I'd love to know how two separate yet not obviously biased sources could verify the authenticity of a private e-mail conversation), we're talking about rape, not a conviction for spamming (and I'm pretty sure the usual punishment is not for the spammer to be raped).
In case you're confused:
http://www.consentiseverything.com/