Gryles is one thing that makes me wonder if Larry has open relationship. It looks like there was something more than just friendship between Harry and Nick. And Louis doesn't look much bothered about it, so I don't think Harry was cheating on Louis (assuming the stories iam telling about Larry are real)
I've always thought it possible that Louis and Harry might have an open relationship - lots of people do. (Although I think there are limits in terms of the ways rumours travel to how much either of them can have ever been seriously on a gay scene).
As I just posted, my story about Nick and Harry doesn't necessarily involve them ever hooking up (although it could - hooking up with someone can be a way to kill a crush).