I'm always firmly of the belief that should get all sides of story before passing judgement. I did think the gf statement could be either a powerful, outing message - or she could be saying as many nasty things as she could, because she's hurting, and he'd be stuck as not really able to defend self without making it worse. All the gaslighting etc could all be made up, I've certainly known people (men and women) make up worse when had been cheated on.
Buuuuut... Did I read right that the snog happened last wed? So either - he told his gf as soon as he came home or woke up next morning, hungover, full of regret. She then knows about it on sat (did look a bit tearful, assumed that was pride) but had accepted it until blew up in press. Seems very unlikely? Surely would have been joint statement like katya and her husband if so?
So is second option - he didn't tell her, she did find out in press and that suggests her side of the story is more the truth.
Such a shame, I don't necessarily think that should quit for being a cheating cock (he will get voted out for sure) but my god this is going to be cringe worthy if he does dance.
I also thought Neil's naked pic was not surprising. Again, I've known plenty of my friends (and Inc me) post a pic of themselves dressed up to nines, or a bit risqué or even the equivalent of well placed rocks to a) make themselves feel better and b) seek approval from others that they are in fact hot.
I can't find any sympathy for Sean. He looked like a single, happy man in those photos/videos. But he wasn't. Alcohol is not an excuse - we've all done stupid stuff when drunk but I never drive, never cheat, never commit murder, never kick a puppy - the list is endless! 
I can't see any excuse for him