Answer
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
Yes, wives should look good for their husbands in Islam as an act of ihsan (excellence), which nurtures love and strengthens marital bonds. The same applies to husbands for their wives.
Answering your question, Sheikh Mustafa Umar, President of California Islamic University, states:
Both husband and wife should try to be the best spouse they can. This is called ihsan (excellence) in Arabic.
One of the ways to be nice to your spouse is to dress nicely, be clean, smell good, and have an overall pleasant appearance and attitude. This helps nurture the love between spouses.
Abdullah Ibn Abbas, a well-known Companion of the Prophet Muhammad (peace be upon him), said that he would make himself look good for his wife the way that she would do so for him.
Sadly, this idea of dressing nicely for your spouse is something many Muslims neglect. They will spend so much time to dress up and look nice when guests come over or when going to a social gathering, but neglect themselves at home.
Both spouses should regularly look good at home. When someone is sick or very busy, it may be an exception, and the natural beauty should still be appreciated, but the default is to put effort into making yourself look good. This helps the marriage be successful.
Feed your curiosity further with the following resources:
Can a Wife Refuse Her Husband’s Bed?
Denying a Wife’s Physical Needs: A Sin?
Privacy between Husband and Wife in Islam
Almighty Allah knows best.