[ Back in Marina, they did fall into some kind of siblingship — probably because he got involved with Kitty so quickly that nothing else got a chance to even begin to develop. He always liked her, always felt comfortable around her but that was it. Nothing physical, even though they've kissed before. There was always someone else that came first, Kitty for him and Cross for her and even here it never came up.
Until now. Until right this moment when he actually sees her for the woman she is and he understands, the loneliness and feeling lost and not quite belonging anymore because once upon a time there was Marina and now there isn't. It's just the two of them, literally and figuratively.
That last bit is what finally makes the cup run over, pushing him to break the standstill and lean in a little closer. Part his lips, tongue darting out to quickly wet them. If she doesn't want to, now would be a great time to say so. ]