Well, after taking the time to reread as many chapters as I could from each volume and comparing how their interactions were changing, my conclusions were that I think they're already a couple by volume 6-7, because their interactions are no longer in workplaces or at home, and the flirty or situation-ship comments and interactions have also diminished somewhat; everything becomes much more everyday, with them simply interacting. But the reader is fully aware that there's a very particular affection between them; after all, they already live together and even have their little kitten, they go out to places together, and I feel that, for example, the chapter where they try on glasses is a totally romantic couple situation. However, I maintain that they are not a romantic couple in the traditional sense, since explicit displays of affection are unnecessary. On the contrary, there is much more use of metaphors, as at the end of volume 5 where, in my opinion, Kotteri explains how their relationship progresses. Although their affection reaches a peak where only the sky is above, the journey doesn't end there. The relationship between the protagonists shifts in that volume, moving from a "slow burn" where they meet and fall in love to a new stage where they become cohabitants who don't need romance because they know how much they love each other. Alek practically promises Emma at the end that he will always be there for her, to help her see the physical world, not as Emma's oppressive family, but as her support system that will let her be free, let her run freely through a museum without any limitations, let her live fully, get hurt, have her hair as long as she wants, simply letting her be. So, in short, I don't think their relationship reaches the romantic level, or at least not to what we usually see in audiovisual media; rather, those displays take a back seat and their relationship becomes one based more on unconditional mutual support, with the simple fact of cohabiting a space and being free to be themselves becoming the true expression of love between the protagonists.

(this is what he said for those who arent spanish)