Amy Robach's former stepson, Nathaniel, has shared a gushing tribute on social media for Valentine's Day - and it's not what you think!POPULAR: Amy Robach and David Muir's relationship amid 20/20 shake-upThe oldest son of Andrew Shue took to Instagram on February 14 to share a sweet photo of himself and his beloved pet dog, posing on the couch at their home."One true love," he wrote in the caption.VIDEO: Amy Robach's rise to fame - and what she's doing nowNathaniel - know as Nate - has been sharing a number of updates on social media since his father and former stepmother split up.MORE: GMA3 viewers all saying the same thing about Amy Robach and Andrew Shue's departureMORE: Kelly Ripa reacts to Live! co-star's long-awaited baby newsHe has been incredibly supportive towards his famous dad, and went away to Montana with the Melrose Place star and his younger siblings, Aiden and Wyatt, for New Year's Eve, sharing a picture of them on social media at the time.Nate's father has faced a difficult few weeks and is no doubt being supported once again by his children.