没你我断了呼吸失你我停了心跳
[méi nĭ wŏ duàn le hū xī shī nĭ wŏ tíng le xīn tiào]
Loosely translates to 'Without you, I stop breathing; lose you and my heartbeat stops.' This indicates that someone is so important as to be irreplaceable, essential to the life and vitality of another person.