i ve heard it said what you don t know won t make you blue but somehow with these words i can t agree cause it s not the things i know you do that breaks my heart you see it s the things that i don t know that s killin me i don t see you when you meet him secretly but i think your arms have held him tenderly so it s not the things i know you do that breaks my heart you see it s the things that i don t know that s killin me the little things that you don t notice hurts me so little things no one but me could ever know i will keep them hidden so no one will ever see it s the things that i don t know that s killin me i don t see you when you meet him secretly but i think your arms have held him tenderly so it s not the things i know you do that breaks my heart you see it s the things that i don t know that s killin me