I think marriage should be abolished all together. People can love and live together. And you can even have kids outside of marriage.
A child born outside of marriage would require both parents consenting to be parents. In case the man doesn't want, a fatherhood test can be conducted.
Some Western Countries still have archaic rules in that regard.
You'd even solve the problem with family reunification unless it's children of the parents. Spouses would need to be viable to move to a country and not just because your husband/wife is living and working in that country.
Abolishing marriage would solve many things
'Living togather' outside marriage and having kids on mass scale would completely destabilize the human civilization as whole.
And that is not a religious perspective, rather, a sociological one.
There are three fundemental things that seperates us from other species and only unique to human.
1. Consciousness.
2. Intelligence.
3. Ability to speak language.
All of which enables us to
organize every aspect our lives, unlike animals.
A loose definition of human organization would be, setting rules in our social, economic and political aspects of our lives. That's how we developed civilizations.
The better a group of people is organized socially, economically and politically, the more likely they would prosper.
From the ancient time, the very first organizing structure of human society is
marriage.
That's because, first and foremost we are a biological organism. Hence, the very process of organizing ourselves starts from the biological aspect of our lives.
If you abolish marriage on mass scale, no matter what ad-hoc solutions you propose to compensate the economic and child custody aspects marriage, the result is still likely to be catastrophic.
When we talk about the violation/corruption of human dignity, people generally assume we are talking in religious terms.
But it is also be a secular term. Corruption of human dignity means, living disorganized in various aspect of our lives despite having the ability to organize ourselves for better.