Why Marty is Worse Than A Jerk
by Laughing Gal
This theory posits that Marty is not just a jerk but a predator, as Vidalia may have been underage when they met.
Since SU deals with unhealthy relationships as well as healthy ones to help the intended audience know the difference, such as Lars' selfish use of Sadie & Lapis and Jasper's harmfully suffocating fusion, it seems for the Human characters that Vidalia & Marty had the most damaging relationship.
We know Greg was 22 when he first met Rose in "Story For Steven" from what he said to Connie in "Steven's Birthday" but we don't really know how old Vidalia was when she hooked up with Marty. Was she underage or was she a few years older than Greg in this episode? Either way, she was much too young for middle-aged (as in old "Farty") Marty with his non-dyed white hair & exaggerrated frown & mouth wrinkles.
In "Story For Steven," Marty - complete with serrated teeth - is portrayed as being more than a jerk but a straight-up predator when it comes to his dating habits. Marty berates Greg for being stuck on one woman when he could be dating "multiple smaller ones." Greg is disgusted and admonishes him with "Ugh, Marty, women are people." Greg also didn't seem too happy seeing Vidalia with Marty when he first opens the van.
Vidalia chewing bubblegum could either be a clue to her being underage or just being immature. It's true that adults also chew gum but it is traditionally seen as more of a childhood pastime.
So how much of a creep is Marty? You decide!
Marty is a predator. Whether he is an illegal one is up to debate.