I get GarandMarine's point. Basically, hanging around an unconscious person you barely know would come across as creepy as hell, no matter how noble your intentions. Marigold was in safe hands with Momo, and Dale could have come back in the morning to apologise and reschedule their date.
But I can also (kind of) see Dale's point of view, too. Marigold was insistent that Dale stay, even in her completely zonked out state. I guess to him it was like an obligation as a friend to make sure she was alright (again, Momo was there, so this rationalisation falls flat).
Personally, I'm of a similar opinion as GM. Dale's a good guy, but
they really haven't been together enough to call it a relationship (spoken by a dude who doesn't have enough experience to make a valid argument
)