"You're not his family, you're his midlife crisis!" - Lexie

Thatcher's medical problems, and his new girlfriend, play a major role in next week's episode of Grey's Anatomy, "P.Y.T. (Pretty Young Thing)." Lexie is far from thrilled.

It's the first few seconds of the promo airing last night that really have fans buzzing, of course. The reason for that is simple: Valentine's Day. MerDer love. Enough said.

Check out our Grey's Anatomy review for a discussion of everything that happened in last night's episode, then watch the promo for "P.Y.T" below if you haven't seen it ...

Follow the jump for an alternate promo from our friends north of the border. The quality isn't the best, but the CTV promo does include some different "P.Y.T." snippets:

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.