Valmiki Ramayana Sundara Kanda Sarga 18 Shloka 19

तासाम् their, पतिः husband, महाबलः powerful, कामपराधीनः under the control of passion, स च and he, मन्दः dull, सीतासक्तमनाः absorbed in the thoughts of Sita, मन्दाञ्चितगतिः walked slowly with measured steps, बभौ became.

Their husband, powerful Ravana under the control of passion looking dull, absorbed in the thoughts of Sita walked slowly as though counting his steps.