Don't worry, be happy.
Did Sabu like the sexy divorced lady? I don't think that he could make Midori cry...
I never understood his relationship with Midori either.Wikipedia says they're engaged, but it was never clear in the series.
Well, Sabu told her "I didn't cheat on you" a few episodes ago, so I guess they are. Many characters of the Sensei are very shy about their love feelings and affairs. The thing's more explicit in the anime.