Well, it isn't what I was expecting, that's for sure.
Now that we know what the big secret is, I do have to say that Akane and especially Nabiki are SERIOUSLY blowing this out of proportion. Ranma's life is not in danger. For the most part, he can lead a semi-normal life. He's no different now than he's ever been. Thus, why the histrionics from Nabs and Akane? I guess for Nabby's part, she realizes WHY Ranma
never retaliated against her nastier schemes.
That said, it does help to explain how Ranma's been able to resist the formidable temptations, and how he doesn't hold grudges where any sane person would.
However, it does seem a bit of a letdown. This chapter just didn't seem as funny as the previous one... I was expecting the big secret to either be something blown way out of proportion, or something really stupid and embarassing.
I'm not sure where you're going with this, but it still looks pretty interesting.