A brief timeline of Elizabeth & Todd's relationship throughout the different series.
Sweet Valley Kids
Elizabeth and Todd are classmates in Mrs. Otis' second grade class. Elizabeth is a tom-boy of sorts and considers Todd one of her best friends.
Even at such a young age there are hints in this series of a crush between the two.
Sweet Valley Twins
Elizabeth and Todd are sixth graders at Sweet Valley Middle School. Todd isn't mentioned in the beginning of this series and only really enters the scene in book #43 Elizabeth's First Kiss, when Elizabeth starts to notice Todd and develops a crush on
him but backs off because Jessica also likes him. Of course, it turns out that Todd has always liked Elizabeth and by the end of book they confess their true feelings. This is the beginning of their couple status as the books
continually mention how Todd is Elizabeth's sort of boyfriend. The rest of the series continues with Todd and Elizabeth "dating" and how they attend dances and parties together.
The Unicorn Club
This series is more focused on the Unicorn Club, hence the series name but at the beginning of the series, the twins are in the seventh grade and Elizabeth joins the Unicorns.
Elizabeth and Todd's relationship is discussed in book #11 Angels Keep Out where they become a couple.
Sweet Valley High
This is the original SV series and is where Elizabeth and Todd are first introduced. According to this book,
Elizabeth and Todd only meet in high school and like Sweet Valley Twins, at first Jessica has a crush on Todd too.
But as usually, we learn that Todd really has feelings for Elizabeth and thus begins Elizabeth and Todd's coupledom in the majority of this series.
This series shows the ups and downs of their relationship as they deal with betrayal, jealousy and most prominently, Todd's move to Vermont. Their story of first love is told and status as high school sweethearts is solidifed in this series.
Sweet Valley Senior Year
This series technically doesn't make sense from what we know of their relationship at the beginning of SVU, but then again Sweet Valley is known for it's inconsistancies.
Elizabeth and Todd are not together in this series but in the last book of the series we do know that they reconnect at their high school graduation and this is supposed to be the set up to their relationship just before they enter Sweet Valley University.
Sweet Valley University
Elizabeth and Todd enter university together but begin to fall into different paths at the beginning of the series. Todd gets caught up in his role as Big Man On Campus and dumps Elizabeth after she tells him that she's not ready to have sex with him.
When Todd's career as a basketball star begins to sour, Todd realizes his mistake in leaving Elizabeth but at this point she has already fallen for Tom Watts. As Todd begins to find himself and turn himself around, Elizabeth and Todd
begin to rebuild their friendship and eventually leads them back to each other for the ultimate book #27 Elizabeth and Todd Forever. Unfortunately, their romance is short-lived when Todd finds out the girlfriend that he was going to leave for Elizabeth, Gin-Yung, is dying.
Sweet Valley Confidential
This series hasn't been published yet but according to the rumours and articles, it's set in a remote community where the Sweet Valley characters are in their 30's. We just have to cross our fingers that Elizabeth and Todd find their way back to each other yet again.