‘Harry wondered whether they had fallen asleep holding hands. The idea made him feel strangely lonely’ - Chapter Ten, Kreacher's Tale, Deathly Hallows. So, what happened!? Here's an idea... Set the first night the trio sleep in Grimmauld Place. :D

‘Come and dance,’ he added abruptly to Hermione.

She looked taken aback, but pleased too, and got up: they vanished together into the growing throng of the dance floor.

Harry Potter and The Deathly Hallows, Ch. 8, The Wedding

'Hermione?’ he said suddenly. 'Where is she?'

'Ron’s taken her inside,’ said Bill, ‘She’ll be alright.’
Harry Potter and The Deathly Hallows, Ch. 24 - The Wandmaker

‘I’m doing it! I’m doing -! Oh it’s just you.’ Said Ron in relief as Harry entered the room. Ron lay back down on the bed, which he had evidently just vacated. The room was as messy as it had been all week; the only change was that Hermione was now sitting in the far corner, her fluffy ginger cat Crookshanks at her feet, sorting books, some of which Harry recognised as his own, into two large piles.
Harry Potter and The Deathly Hallows, Ch. 6, The Ghoul in Pyjamas