Divorce is fine. Lying to your partner by cheating them is not.

Yes, but "left wife for secretary" not necessary implys cheating. (even though it is likely)

I love how the first page (Ch. 1) tries to show that 'terrifying' calculus symbols have very simple meanings, and so there's no reason to run away.

Less pleased, though not at _all_ surprised, that the book addresses 'fifth form boys', with no mention of girls.