Sayyidah Asma' bint Abi Bakr (may Allah be pleased with her) said: A woman came to the Prophet (peace and blessings be upon him) and said: O Messenger of Allah! I have a co-wife. Is there any sin on me if I make a show of being filled, on my husband's part, with what he does not give me? The Messenger of Allah (peace and blessings be upon him) said: "Whoever pretends to be filled with what he has not been given is like one who wears two garments of falsehood."
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 20695