Valmiki Ramayana Ayodhya Kanda Sarga 24 Shloka 12

स्त्रियाः for a woman, भर्तुः husband's, परित्यागः desertion, केवलम् only, नृशंसः किल is a cruel act indeed, विगर्हितः is abominable, सः that, भवत्या by you, मनसापि even in mind, न कर्तव्यः must not be done.

For a woman, to desert her husband is a cruel act. You must not do that which is contemptible even to think.