Mut'ah has the purpose of what you're saying. You might also want to see here. Marrying a second wife is a huge commitment. A woman may enjoy a single sex night. But no woman would want to be your your sex partner for an eternity. She would want commitment ie if you're marrying her then you give her your everything. Your heart and not just your body. Similar to what UmH has said.
Have you heard of a narration that a husband must inform his wife of such? I haven't.
Technically speaking in Islam a husband is not bound to his wife. So a wife has no right of such. Hence it's not cheating against her. Though in today's world, among non-Muslims, being with another woman is the very definition of cheating. From what I understand in Islam cheating is to not do justice.
And the definition of justice is not exactly what you think. I mean what would a man do if he has 3 wives? What is he do with the forth night?
Let's see what the hadith say:
تهذيب الأحکام , ج 7 , ص 420
عَنْ حَمَّادٍ عَنِ الْحَلَبِیِّ عَنْ أَبِی عَبْدِ اللَّهِ ع قَالَ سُئِلَ عَنِ الرَّجُلِ یَکُونُ عِنْدَهُ امْرَأَتَانِ إِحْدَاهُمَا
أَحَبُّ إِلَیْهِ مِنَ الْأُخْرَى أَ لَهُ أَنْ یُفَضِّلَ إِحْدَاهُمَا
عَلَى الْأُخْرَى قَالَ نَعَمْ یُفَضِّلُ بَعْضَهُنَّ عَلَى بَعْضٍ مَا
لَمْ یَکُنَّ أَرْبَعاً
I asked Imam Saidqh about a man who has two wives and one is more
favorable to him, can he favor one over the other? Imam said: Yes he
can favor, til they are not 4 wives.
I also saw in another hadith, that if a husband marries a virgin woman, then that woman has the right of 7 consecutive nights. If she's not virgin then she has the right of 3 nights. It's kind of similar to honeymoon :). After that I guess things back go to normal.
Is this against the verses of Quran?
الکافی، کتاب النکاح، باب فیما احلّه الله
عزوجل من النساء
- قَالَ سَأَلَ ابْنُ أَبِی الْعَوْجَاءِ هِشَامَ بْنَ الْحَکَمِ فَقَالَ لَهُ أَ لَیْسَ اللَّهُ حَکِیماً قَالَ بَلَی وَ هُوَ أَحْکَمُ
الْحَاکِمِینَ قَالَ فَأَخْبِرْنِی عَنْ قَوْلِهِ عَزَّ وَ جَلَّ
فَانْکِحُوا ما طابَ لَکُمْ مِنَ النِّساءِ مَثْنی وَ ثُلاثَ وَ رُباعَ
فَإِنْ خِفْتُمْ أَلَّا تَعْدِلُوا فَواحِدَةً أَ لَیْسَ هَذَا فَرْضاً؟
قَالَ بَلَی قَالَ فَأَخْبِرْنِی عَنْ قَوْلِهِ عَزَّ وَ جَلَّ وَ لَنْ
تَسْتَطِیعُوا أَنْ تَعْدِلُوا بَیْنَ النِّساءِ وَ لَوْ حَرَصْتُمْ فَلا
تَمِیلُوا کُلَّ الْمَیْلِ أَیُّ حَکِیمٍ یَتَکَلَّمُ بِهَذَا ؟ فَلَمْ
یَکُنْ عِنْدَهُ جَوَابٌ فَرَحَلَ إِلَی الْمَدِینَةِ إِلَی أَبِی عَبْدِ
اللَّهِ ع فَقَالَ یَا هِشَامُ فِی غَیْرِ وَقْتِ حَجٍّ وَ لَا عُمْرَةٍ؟
قَالَ نَعَمْ جُعِلْتُ فِدَاکَ لِأَمْرٍ أَهَمَّنِی إِنَّ ابْنَ أَبِی
الْعَوْجَاءِ سَأَلَنِی عَنْ مَسْأَلَةٍ لَمْ یَکُنْ عِنْدِی فِیهَا شَیْ
ءٌ قَالَ وَ مَا هِیَ؟ قَالَ فَأَخْبَرَهُ بِالْقِصَّةِ فَقَالَ لَهُ
أَبُو عَبْدِ اللَّهِ ع أَمَّا قَوْلُهُ عَزَّ وَ جَلَّ فَانْکِحُوا ما
طابَ لَکُمْ مِنَ النِّساءِ مَثْنی وَ ثُلاثَ وَ رُباعَ فَإِنْ خِفْتُمْ
أَلَّا تَعْدِلُوا فَواحِدَةً یَعْنِی فِی النَّفَقَةِ وَ أَمَّا
قَوْلُهُ وَ لَنْ تَسْتَطِیعُوا أَنْ تَعْدِلُوا بَیْنَ النِّساءِ وَ
لَوْ حَرَصْتُمْ فَلا تَمِیلُوا کُلَّ الْمَیْلِ فَتَذَرُوها
کَالْمُعَلَّقَةِ یَعْنِی فِی الْمَوَدَّةِ قَالَ فَلَمَّا قَدِمَ
عَلَیْهِ هِشَامٌ بِهَذَا الْجَوَابِ وَ أَخْبَرَهُ قَالَ وَ اللَّهِ مَا
هَذَا مِنْ عِنْدِکَ
Kafi, Book of Nikah, chapter women who marrying them is halal
Muhammad ibn al-Hasan says: Ibn abi al-awja asked Hisham ibn al-Hakam, Isn't Allah Wise?!
Hisham said: Allah is Hakim. He's the wisest of judges!
Ibn ib al-awja said so tell about the verse: “And if you fear that you will not deal justly with the orphan girls, then marry those that please you of [other] women, two or three or four. But if you fear that you will not be just, then [marry only] one”. Isn’t this mandatory/wajib?
He said: yes!
Ibn abi al-awja said: tell about this verse: “And you will never be able to be equal [in feeling] between wives, even if you should strive [to do so]. So do not incline completely [toward one].” Which hakim says such?!
Hisham ibn Hakam didn’t have an answer to this question. So he traveled to Medina and reached out to Imam Sadiq. Imam Sadiq said that you’ve came here at a time that isn’t for Hajj.
Hisham said: I’m here for something important. Ibn abi al-awja asked something I couldn’t answer.
Imam Sadiq said: What is the question?
Hisham told the whole story.
Imam Sadiq: The verse “And if you fear that you will not deal justly with the orphan girls, then marry those that please you of [other] women, two or three or four. But if you fear that you will not be just, then [marry only] one”. Is about giving nafaqa. But the verse “And you will never be able to be equal [in feeling] between wives, even if you should strive [to do so]. So do not incline completely [toward one].” Is about love (مودّه).
When Hisham returned and told the answer to Ibn abi al-awja, Ibn abi al-awja said: I swear! This answer is not from yourself, you got it from somewhere else.
It's allowed, but not recommended. Having a secret life is never worth it.
Justice doesn't mean a just number of nights in between women. Each woman deserves only one night in every 4 nights. If he has one wife, he can sleep 3 nights in a hotel (stupid idea) and one night with her. If he has two wives, he can sleep 3 nights with one and only one night with the other.
Justice is about giving the same amount of nafaqa. He can't say, this woman has PhD so I'll give her $500 a month, and that woman has no degree so I'll just give her $100 a month. Yet if her wife who has PhD has more expenses e.g. she need to buy clothes more frequently for her work, then that's a different thing. It's not nafaqa. It's just more cost. I would assume that equal nafaqa means equal housing, clothing, vacations, food, etc ie he can't say I'll get one a penthouse and a dungeon for the other.