Valmiki Ramayana Aranya Kanda Sarga 13 Shloka 5
Original Shlokaएषा हि प्रकृतिः स्त्रीणामासृष्टे रघुनन्दन। समस्थमनुरज्यान्ति विषमस्थं त्यजन्ति च।।3.13.5।।
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रघुनन्धन O delight of the Raghu race, आसृष्टे from the beginning of creation, एषा this is, स्त्रीणाम् of women, प्रकृतिः is the nature, समस्थम् when everything is normal, अनुरज्यन्ति they enjoy, विषमस्थम् in hard situations, त्यजन्ति च they give up.
O Rama, the delight of the Raghu dynasty from the beginning of the creation women, by nature, keep the husband company when all goes well and give them up when hard times come.