Congratulations to him.
As long as the first wife is happy, consenting, and well cared for, there’s really no issue with it.
The practice of having multiple wives is prevalent since the stone age and was once common across nearly all cultures including Hinduism. It’s just that Islam as a culture has remained largely primitive and patriarchal that this practice is still prevalent whereas most other societies evolved through socio-economic reforms making polygamy less practical and far less convenient for most men.
Many Hindu kings had multiple wives, the Sikh Maharaja of Patiala famously had hundreds. Even up until India’s independence, it wasn’t unusual for ordinary Hindu men to have two wives, particularly those who migrated from villages to larger cities. Often, the first wife remained in the village (married at a very young age), while the man took a second wife in the city. In fact, both of my grandfathers, on my father’s and mother’s side, had two wives each. The city wives were treated by both as their primary partner, while the earlier marriages became just symbolic over time.
Dharmendra famously married Hema Malininwhile he was still married. Raj Babbar married Smita Patil while he was still married. Bony Kapoor married Sridevi in a similar manner.
Non-Muslim men often make a big deal about Muslims being allowed up to four wives, but realistically, managing even two is difficult unless one has significant means. Usually it’s the very rich or the extremely poor who do it as both do not give a damn. For the middle class men, who are constrained by financial resources and morality, this is often not practically possible.
That’s precisely why non-Muslim men innovated the idea of the extramarital affair, a way to enjoy multiple romantic relationships without the formal responsibilities or social scrutiny that come with marriage.
And in recent years, we’ve seen a modern evolution of that concept, the “work husband/work wife wherein people form romantic relationships in high stress work environments.