Good decisions come from experience. Experience comes from bad decisions.
Dude... it sounds to me like you somehow want there to be something going on. To me I see a young girl stand with her back against a wall, with some young dude sitting on a table telling a joke or whatever and he is probably drunk (beer beside him), and in his story telling or while laughing he leans forward. She looks to be recoiling a little while laughing because he is violating her "cultural space" by accident. And someone caught it on film because they were photographing Mrs. Fabulous in the foreground.
She isn't "Crotch to crotch" with anyone... nor "standing between his legs" or any of that other mellow dramatic BS.
She may be stepping out on you man... but you can't see it from that picture. At all. Get over it.