As soon as I saw the title, I thought-another bob question.
It's about a public commitment. It's not strictly speaking necessary but it helps society run smoothly.
A lot of stuff in our society isn't strictly necessary. Funerals aren't necessary either. But they are a rite of passage, so to speak, & help with closure for the family.
Are graduation ceremonies essential? Of course not.
So why have any of these things? Because they help crystallise things.
When people commit to marry, what they are saying is they intend to set up life together & that they will both look after any children that come along.
What does it give people? It gives some sense of security for the male and female and it makes bringing up children easier. It's not that these things can't be achieved without marriage, just that it makes the process easier if there are 2 parents on hand.
People seem to need rites of passage. If you look at children, there are many ceremonies amongst various religions that signify a passage from childhood into adulthood. For the non religious, you now have those graduations. The move from one phase of life into the next. For those kids that don't have any of this, or no sense of belonging to family or community, you have gang initiations. Same sort of thing.
Marriage or commitment to relationships wouldn't be around unless it helped humans & society in some way. the fact some relationships break down doesn't change that. Often those people then move on to another committed relationship of some sort.
