Before the Wedding

"Kurt ran his thumbs over Blaine's knuckles once. 'I gotta do this properly. You deserve it.' Blaine's face fell. 'Oh. I…' 'No' Kurt interrupted, eyes widening. 'That's… that's not what I meant. Of course I – Okay, hold on a second.'" What happened between them being ambushed by Brittana and Sue and them walking down the aisle.