"Erik," Charles says, and he can feel his heart breaking already in his throat, a terrible and sharp pain that tears right through him, "Yes."
It's the reversal of how that has gone before, that exchange of precious words, like Erik as supplicant like this feels wrong--for Erik to kneel like that as if he can't stand, not as if he chooses this, and Charles corrects what he feels as a yawning chasm by falling to his knees as well and cradling Erik's face in his hands. He strokes his thumbs over Erik's cheekbones as if there are tears there to wipe away, and his own eyes are welling up as he looks at Erik.
"I love you completely. With all of my heart. Erik--" Charles tips their foreheads together as if touch alone will draw out whatever poison is hurting Erik so, and the awful thing is that he could do exactly that "--Erik. Oh, Erik."