Spring Green

I have that same kink about a cold, emotionally cut-off person and a love interest who gets that person to warm up a little, also getting it from romance novels. I think perhaps that's why the KuroxFai relationship in Tsubasa is so interesting, because which character you think fits each role early on turns out not to be the case. It looks as though Fai is the stereotypically feminine one who warms up cold Kurogane, but then it turns out Fai's emotionally-connected manner is a front for some deeply repressed emotional baggage, and Kurogane, who seems to be the too reserved masculine partner, is the one who's really doing the emotional work in the relationship and trying to connect to the other one.