Michael was warm and loving to Kay in '45, but when he came back from Sicily and reconnected with her in New Hampshire in '47 (wearing that ridiculous homburg hat and looking like a pint-sized banker), he might have been negotiating a merger or acquisition with a weaker company--in fact, he wanted to own Kay (listen to the bloodless way he said, "I love you"--it's a wonder she didn't keel over from fright).
His actions during the Tahoe shooting were instinctual (good, protective instinct) but that scene wasn't about warmth--it was about survival. Kay certainly didn't take it that way--after the shooting, when she was clutching Mary, she gives him a look that would kill. It was all over between them at that point.
Why do you point their meetup to '47? GF seems to make plain that he met her at the schoolyard in 1951 ("That was seven years ago" she says of his promise to have the family be legit, in 1958).
But yes, the whole meeting is very almost creepy. It is totally a business arrangement to him. It's like he acquired her because life dictated he needed heirs and thus needed a wife, and she was the easiest to obtain since they had previous history - nothing more. I think whatever humanity lived in Michael (and he was always cold, as we see in the flashback to 1941) died in Sicily.
