And I don't think Justin wanted romance, at least not in the flowers and candy sense, he wanted reassurance, something that was clear enough that he could be sure he wasn't just seeing what he wanted to see and banish all his newly acquired doubts.
I agree with this so much. I think the problem is that at the same time, Ethan came along. Ethan simply exuded reassurance, the fact that it was in a romantic way was just a happenstance that influenced Justin's desire for that "something else", that reassurance. He would've wanted reassurance all the same, but likely not in this specific form of roses, chocolates and floor picnics.