@AlDanvers
Do you really believe a relationship isn't committed if there's no marriage?
A lot of people think like this.
The law doesn't take a relationship with a non-married couple as seriously as one with a married couple either.
I have known a number of cases over the years, where a couple have been together 15-20 years, sometimes 25 or more, and one of them dies, and they don't even get a sympathy card from most people, OR a single day off work.
Conversely, I have known a few couples who were only married 5 or 6 years, and together for just 8 or 9 years, and when their spouse died, they had huge collections at work, were given a week off, had bundles of cards and gifts, and had the utmost sympathy from everyone. The non-married people got shag all, even thought they were together 3 times longer...
As I say, like it or not, even in 2021, the vast VAST majority of people will not take a couples relationship very seriously if they are not married. Not even if they have children. They will be taken more seriously if they have children, but still not as seriously as couples who do. The couples with children who are married, get a lot more respect.
I am not saying it's right, but that is how it is. I have to say, I don't take a relationship very seriously if they're not married either. That's just how I feel.
That doesn't mean not getting married is any less committed.
@DrSbaitso
Of course it's less committed. Doesn't mean it's always wrong not to do it, but it's a level of commitment above not doing it. It's a legal commitment, a contract. It must mean something if people refuse to do it.
Exactly! If the people who are daft enough to believe 'it's only a piece of paper' then why NOT get married? After all, it's ONLY a piece of paper. 
I also call bullshit on 'men don't want children only women do.' In my social circle, the men have very much wanted children, as much as the woman for sure. Including my own DH. He was ecstatic when I said I was pregnant with our first, and even now, feels extremely proud and privileged and happy that he is a dad. My dad was the same; he absolutely adored me and my brother.