Canto 3 -
Araṇya-kāṇḍa
Chapter 61: Rāma’s Lamentation
Text 3.61.6

सीतया रहितोऽहं वै नहि जीवामि लक्ष्मण॥

sītayā rahito ’haṁ vai na hi jīvāmi lakṣmaṇa

sītayā = Sītā; rahitaḥ = without; aham = I; vai na hi = never; jīvāmi = can live; lakṣmaṇa = Lakṣmaṇa.

Lakṣmaṇa, I can never live without Sītā!