Confessions?

I don't think they ever did...

They essentially have, not by saying "I love you" point blank, but a number of emotional moments with "never leave me" in different variations. People express and confess their love differently

Yes, they have. They've not screamed at the top of their lungs ''I love you!'' but it's been heavily implied. Just read the latest chapter, it's disgustingly mushy. :)