A Line Relationship is a polyamorous relationship dynamic in which younger partners are added to the relationship as older partners age. The oldest partners may not date the younger partners, depending on how young they are. However, line relationships consist of only individuals who are the age of consent. The reasons for having a line relationship varies, but one example would be wanting to have a long-lasting relationship that may last several generations.
Flag
The line relationship flag was coined by Deviantart user NonMonoPrideFlags on January 16th, 2016.
Resources
https://www.deviantart.com/nonmonoprideflags/art/Line-Relationship-Pride-Flag-584865559