Shloka 3.18.2
शूर्पणखाविरूपणम् (The Disfigurement of Śūrpaṇakhā)
कृतदारोऽस्मि भवति भार्येयं दयिता मम।त्वद्विधानां तु नारीणां सुदुःखा ससपत्नता।।।।
kṛtadāro 'smi bhavati bhāryeyam dayitā mama |
tvadvidhānāṃ tu nārīṇāṃ suduḥkhā sasapatnatā ||
“Lady, I am already married; this is my wife, dear to me. For women like you, becoming a co-wife is indeed a great sorrow.”
O lady I am married and here is my wife who is dear to me. To be a co-wife to some one is indeed painful for people like you.
Dharma upholds marital fidelity and social order: Rāma states the truth of his married status and implies that disrupting an existing marriage brings suffering and conflict.
Śūrpaṇakhā propositions Rāma; he responds by affirming that he is married to Sītā and frames co-wife rivalry as painful.
Rāma’s satya and maryādā—truthful self-disclosure and commitment to his lawful spouse.