There are several ways to create page breaks in CS6 (a good thing). You must be using one or more of these:
(1) If you've created a book file, each chapter will create an XHTML file.
(2) You've specified one or more paragraph styles (in Paragraph Styles panel menu > Edit All Export Tags to split the file, and turning on splitting in the export dialog.
(3) You've modified a graphic in Object > Object Export Options to cause a break before and/or after the graphic.
or you've inadvertantly included a character which is formatted with one of those splitting paragraph styles. That's all it takes, just one character, and you get an extra break. Happened to me just yesterday since I was in a hurry.
Thanks Steve - By switching to "do not split" in the advanced column, I got the desired xhtml files. Thanks!