I think Bradley and Colin are emotionally in love with each other. Their mutul affection is JUST TOO MUCH INDEED. It is not about the quest thing (maybe somebody want to commercialize that) but rather from the on-set behaviors whenever they are together (especially those from fan report when they are not aware of).
So they are emotionally in love. But I am not sure about the physical thing. But come on, Brad and Col, one life, one love, get on with it.