Adultery - in a kids' book?

A few weeks ago I read The Thieves of Ostia to the kids. This is one of a 15-book series (The Roman Mysteries by Caroline Lawrence) set in ancient Rome. I had heard good things about the books and my kids were interested but not enough to read the series on their own, so I decided to read the first book. Then, I said, they were on their own.

The book was pretty good, not outstanding, and not really the kind of thing I like to read aloud. I like to save my reading time for books that my kids are not capable of reading, or comprehending, or processing on their own.

So we finished the first book and got the 2nd from the library so one of them could start it. But then we all got sick, or tired, or something, so I caved in and started reading it. It was quite exciting and we finished it tonight. And now I see that I will have to read the whole series to them, because one of the themes in this books is adultery. Or, to be precise, an accusation thereof.

No, the actual word is not used, but there is an accusation that a man's wife and his friend were were lovers, and that relationship produced a child. Yes, in a book for the 9 - 12 set.

Otherwise the books are good historical fiction, worth reading. The one we finished tonight, The Secrets of Vesuvius, gives a good picture of life under the volcano. It does not have a pat happy ending (though the main characters in the series, 4 children, all survive, of course). There are characters who follow that new religion, Christianity, and people who persecute them. There's excitement and fun and history.

But now I can't trust them to be appropriate for my kids to read on their own. Even 12 is too young to need to read about adultery (even if just imagined) in a novel. A novel!

But we're not doing the whole 15 books in a row. We did 12 in a row with the "Swallows and Amazons" marathon last year. The Roman Mysteries are fun, but they do not compare with Arthur Ransome's series of kids in England's Lake District. And there's no adultery to worry about either.