While Lauren, Audrina and later Kristen created story lines with their never ending boy drama, 24-year-old Lo has always been the stable one.
And according to online reports, he has been shopping around for engagement rings.
But a spokesperson for Bosworth, who now runs her own advice blog, The Lo Down, has said that the couple have parted ways.
'Lo and Scott are no longer together, but remain good friends,' her rep to People.
Lo Bosworth says a battle with depression led to her "worst year ever" in 2016.