"You will be my boyfriend."
Translation:Tú serás mi novio.
I'm pretty sure there's more to it than that ... http://www.studyspanish.com/lessons/persa.htm
'In Spanish, when the direct object is a person, it is preceded by the preposition "a." ' (Plus pets etc :) I guess I'm asking why 'boyfriend' isn't considered a person in this sentence.
You either don't use 'a' in the presens so why in the future tense? for that's the preposition 'a' is not needed. Presens: "You are my boyfriend" -> (Tú eres mi novio)
I know, that is true. But the surely estar is even more appropriate here. I will take it to my Spanish group who will be enthralled no doubt!