Before Volume 2Edit
The timeframe that Bo and Kara got married is unknown, however it was at least six months before The Secret Life of Bo Baxter, which is an approximation of Baby B.'s age. This means that Kara and Bo were probably married before Elwood, and maybe even during Arthur Read's second grade year.
Buster and Bitzi find out about Bo's new family in The Secret Life of Bo Baxter. It is revealed, much to Bitzi's horror, that Bo has remarried a beautiful and perfect woman named Kara, and their baby son is Baby B. Bitzi pretends that she doesn't care, but it's obvious that she is hurt and jealous.
Bo and Kara are seen in I Wanna Marry Harry, Part 2, and they still seem happy after the Bitzi incident.
Bo and Kara still have a perfect relationship in Bitzi Goes Ballistic. However, Bitzi's hatred and jealousy of Bo soon transforms into insanity. She plots to murder his family, and one day at the grocery store parking lot, she does just that. Bitzi runs over Kara and Baby B., killing them. Kara's last words are, "NO! Someone please save my baby!"
After Kara's deathEdit
Bo is heartbroken to discover that his family is dead. He is the only one attending their funeral, and he mourns for them passionately. When Bitzi reveals that she killed his family, Bo is infuriated. This leads to Bitzi's trial and eventually her execution (Loved and Lost).
Later, Bo was murdered by his son, Buster Baxter, on October 6, 2014 (Dear Diary, Part 4).