I’m not Indian, so I might not be getting the full picture here, but this seems like a mostly positive move. Of the three denial reasons, I’m very in support of the latter two and against the first, but it seems less harmful to bar married people from living with non marital romantic partners than it does to allow people to work around the age and consent requirements for marry by simply not legally marrying the child and/or unwilling participant. That’s how, for example, the US has sister wives even though polygamy is illegal. (I’m not against fully aware adults being polyamorous, but that’s not the same as polygamy. )
What’s the issue you see with this law itself? I can definitely see a problem if it’s unevenly enforced, but the law itself seems like a net positive.