There are four yugas: Satya Yuga, Dvapara Yuga, Treta Yuga, Kali Yuga.
It is well known that dharma is relative w.r.t. the time. Many dharmas which are valid in one yuga may not be valid for the other. Inorder to remove the ambiguity, dharma sastras and other scriptures come into the picture.
With this context, I got the following doubt.
I read one story of Oghavati from Mahabharata, and words of Rama from Ramayana.
Observe the following lines by Sudarsana:
The son of Agni, O king, said to Oghavati,--Do thou never act contrary to (the wishes of) those that seek our hospitality. Thou shouldst make no scruple about the means by which guests are to be welcomed, even if thou have to offer thy own person.
Similarly observe the following lines by Rama:
"O gracious lady! Therefore, this has been spoken by me today, with a resolved mind. Set you mind on Lakshmana or Bharata, as per your ease. O Seetha! Otherwise, set your mind either on Shatrughna or on Sugreeva or on Vibhishana the demon; or according to your own comfort."
and also these lines by him:
"Without being asked, I myself would have gladly offered even Sita with kingdom, even my life, loved ones and wealth."
It is well known that Ramayana happened during Treta Yuga and the story of Oghavati happened mostly before Dwapara Yuga.
Even it seems to be extreme step in those yugas also. It was still treated as dharma during those days.
Is that dharma of giving/offering own wife to others is invalid in Kali yuga according to scriptures? If yes, which scripture mentions about relativity of this particular dharma?