I alway's thought that Kay and Michael are "soul mates" but they are incompatable in living together. Each of them hates the idea of one hating the other. In all, I don't think they would ever get together.

Although Mike is essentionally a loner and somewhat selfish, Kay knows that Michael loves his children, but she never knew to the extent until she saw Mike craddle Mary in his arms and yelled out. I don't think Kay blames Mike for her death because it is obvious that the bullet was meant for Michael, not Mary. Plus she commented to Mike how "dangerous" is it for him to be in Sicily.