Bismihi Ta'ala
I would like to firstly address this issue in point form:
1. Marriage and spousal relationships falls within Islamic Shari'ah, given to us by Almighty God, and the details of which are in our Fiqh.
2. Marriage in Islam is something recommended, but if one was to fall into sin, marriage would become obligatory upon them.
3. It is important to distinctively distinguish between the jurisprudential laws of marriage, and the social, moral and spiritual dimensions of marriage and a relationship.
4. The entity of marriage is sacred, based not only on certain rights, but also on moral obligations and commitments.
5. Anything that disrupts the harmony of this entity must be avoided.
Secondly, there are a variety of issues that are related to this seemingly simple question. Our social duties are not easily dealt with, and nor should we look at Islamic laws in abstract form, or just black and white.
Yes, from a fiqhi perspective, as a ruling, a husband does not need the shar'i consent of his wife, but that is not because Islam aims at belittling the status of the wife, or seeing her feelings to be of no value.
Like other religions, Islam permits a man to have more than one wife, and this is not something we should shun away from.
We also realise that as Muslims we conform our beliefs and views with Islam, the Quran, and the authentic Sunnah. Not modern norms, or non-Islamic social customs and practices.
Of course, there are many conditions placed for the purpose of regulating marrying multiple wives. Some jurists have added some further conditions. The nature of a man is different to that of a woman, in their physiology, their mentality, and other differences.
A husband must be absolutely just and fair between the wives. In accommodation, in expenses, in food, in time, in expressions. If he cannot do this, then he cannot get married.
Divorce is detested in Islam, and so if the husband is having problems with his, or his wife is sick, or she is in jail, or away from him, then he should not quickly opt for ignoring, mistreating or abandoning her.
Also, we can see in I.R. Iran, that it is required for the husband to have legal consent of the first wife, should he wish to marry a second wife, and this is also on the condition that he has a legitimate reason to marry a second time.
There is also a difference between "getting permission" and "consulting and informing." If she is ok with it, the fine, but if she is not ok with it, as he has the choice to marry, she has the choice to stay, or to get divorced. However, the first wife's consent is not a prerequisite for the husband to remarry. The marriage contract would be "valid," but this does not mean that the husband is doing right as far as his social/moral obligations to his household. This is why such a topic has many dimensions to it.
Also, bear in mind that the wife has the choice of stipulating pre-marital conditions, and one of them is that if the husband wishes to re-marry, the wife has a certain options for her to choose from to ensure her requirements.
It is for these reasons that a husband must focus on the foundations of marriage, and ensure a healthy relationship, based on commitment, loyalty and the best of moral conduct. A man must also commit to avoid pursuing his sensual lusts outside of his household, for the sake of preserving the relationship. Just because it is permissible, does not mean that he needs to perform it, especially if it will destroy the entity of his marriage and family life.
It is for the wife to also create a positive productive atmosphere in the household so that the relationship continues to flourish and each stay strong with each other.
Wassalam
