- Alana Hamilton: Stewart and Hamilton were in a relationship in the 1970s, and their breakup is said to have inspired Stewart's hit song "Da Ya Think I'm Sexy?"
- Britt Ekland: Stewart and Ekland were married from 1979 to 1984, and their divorce was reportedly quite contentious.
- Rachel Hunter: Stewart and Hunter were married from 1990 to 2006, and their divorce was also highly publicized.
- Penny Lancaster: Stewart and Lancaster have been married since 2007, and their relationship is considered to be one of Stewart's most successful.
While these relationships have all had their ups and downs, it is difficult to definitively say which one caused Stewart the most heartbreak. However, it is clear that Stewart has experienced significant heartbreak throughout his romantic history.