Ramayana 5.21.4

अकार्यं न मया कार्यमेकपत्न्या विगर्हितम्।।।।कुलं सम्प्राप्तया पुण्यं कुले महति जातया।

akāryaṃ na mayā kāryam ekapatnyā vigarhitam | kulaṃ samprāptayā puṇyaṃ kule mahati jātayā ||

Born in a noble lineage and wedded into a virtuous family, devoted to one husband alone, I must not do this forbidden, shameful deed.