Shaun (Last of the Time Lords)
Shaun (Last of the Time Lords) was a student that shared housing with Martha Jones's friend Vicky and three other students. Although Vicky was in love with Sean, he never even looked at Vicky twice. Vicky wasted five years obsessing over Sean, talking about him all day long and never looking at anybody else while he was around. Vicky was warned by Martha many times to "get out" because Sean only liked Vicky and nothing more would happen. Sean and Vicky's story was used by Martha as a comparison to the doctor and herself. Martha told this story to explain why she chose to leave the TARDIS and travelling with the doctor because nothing more would happen either between Martha and the doctor even she did stay.