He likes her scars. They remind him that she's human, that in some ways she's just like him. He has scars too, they cover his entire body, some places there is nothing but scar, others it looks like he's completely normal, he has discovered this is the same for her. The ones that stand out are the ones that show bright white on tan skin as their clothing falls to the floor, the new scars that will develop after a hard mission leaving difficult wounds, and then there are those faded by the passage of time. He loves her scars.
End, count it up :-)