i for one think the way Jeph wrote the scenes is 100% realistic, i totally see this fight happening in RL.
as Avra mentioned its not something you'd use as an opening line the only question is should you hide that fact or not, if so then for how long.
as far as Dora's reaction (and im expecting to get flamed here) i wouldn't expect any Less from a gf, then again that's my opinion.