Yes, the marriage certificate has nothing to do with the love and committment. But it is a nice thing to have if you are going to - oh, adopt a child from Korea (have to be married three years - my son is from Korea).
My mother in law had been divorced for years. And she and her live in boyfriend had been together fifteen years. A few years ago, they got married. Why? - because she was nearing retirement and wanted his benefits. She, like recent college graduates all over the country, got married for health insurance. She will also qualify for his pension, his SSI survivor benefits (if they are better than hers independant ones, and they may be). If he dies, she will inherit his estate with somewhat less messiness.
Now, its possible that none of this mundaneness will ever interfere with your relationship. That’s cool. But for a lot of people, this mundaneness of needing to have the piece of paper makes things a lot more livable.
This gets, however, into the whole marriage or not debate and away from the pre-nup discussion.
BTW, I don’t have a pre-nup. When I married my husband we were both struggling. We had similar backgrounds (my husband was not expected to outearn me x5) and we were pretty sure that kids were in the fairly near future. I’d been over his bankruptcy records and managed his finances for two years - I knew exactly what he did and didn’t have. I had somewhat more, but not enough to worry about.
But if I were to be in a position of remarrying now, I’d want my children’s potential assets protected (their college funds are held by me) and their security to adulthood ensured. I wouldn’t want to have to sell my house and divide up the assets because I was blinded by love into marrying a jerk. I’d want to be sure my retirement fund remained mine and that I didn’t have to pay spousal support to a mooch.
And I saw my brother in law - a guy with little - but something - marry a girl with a lot of debt he didn’t know about. And then he inherited a good bit of money. And now he is considering a divorce that will leave him with less than he started with. He loved her and trusted her, and the trust was misplaced. And her take on the whole thing was “its love, we are in it together, it shouldn’t make any difference what either of us has or doesn’t have.” And maybe he is a shallow person, but I don’t think he expected “in it” to be $150,000.