Love interest?

Okay so I've had this dilemma and cannot decide what I want to do between two of the main characters. We don't get a lot of background on Teancum and his crush Elatea. Originally the idea was for her to be kidnapped by Lamanites which spurred his drive to become the warrior he inevitably will become. As I've thought on the matter, I've decided Elatea will not be kidnapped, but will still remain a motivating factor for Teancum throughout the series. Now the question: How serious should I make the relationship? Should it be the type that starts as a simple friendship and eventually blossoms into something more, or should it be the on again off again style, or something entirely different?
Some background info: The book begins with Teancum spying on Elatea (peeping tomming if you will) and he appears to have been completely obsessed with her since reaching puberty. They share some pretty traumatic experiences in the beginning. I am thinking of playing it out as her thinking of him more as a brother and him trying to be noble about his obsession valuing the friendship more than his own desires for her. What do you think? Has this style of romance been overplayed a little?