If your wife ever visits Delphi with you and isn't immediately entranced by the beauty of that place, then the problem is definitely with her, not you! The ruins are spectacular but staring down at that valley (ideally you'll pair it with a little snack and some wine) is one of my favorite memories of Greece.
I agree with everyone that Sparta is mostly worth skipping if you're looking for ruins, but... i actually quite liked it. The ruins are minimal but they are there, and you're pretty much left entirely to yourself (although this may have changed, i was last there a decade ago). In fact, the place was so abandoned that there were looter's pits *everywhere*. Roman-era potsherds everywhere, scattered about the amphitheater and among the olive groves which now lie atop most of the ruins. Sad to see, but also interesting to see just how plentiful this material is for those of used to seeing even the most mundane artifacts locked up behind museum glass. Just don't try to take a souvenir!!