This could be the worst advice I've ever seen on this forum.
What is the basis of such a suggestion?
A successful marriage.
And that of a friend of mine who wrote
a book on ordinary people's finances, which many people have followed with both financial and relationship success. One of the things he suggests is a monthly "financial date night" where you sit down and discuss your mutual desires and goals financially. Over time as you get things sorted there's less finance talk and more other talk. Obviously there are other ways to do it, but the point is that you're a couple and you sort things out together, and check in regularly to see if anything's changed.
We watched
Marriage Story recently, and felt this depicted a lot of failed marriages we've seen. They didn't have any fundamental incompatibility, they just got caught up in the everyday bullshit and grind, and the woman sort of feebly raised some of her dreams which he ruthlessly ignored in favour of his own. Having regular talks one-on-one about their goals and lives might have avoided that.
I've been reading
Mistakes Were Made: But Not By Me recently, and they've a whole chapter on marriage, saying, "self-justification is the assassin of marriage." We all do good things and bad things, but are the things I do because of circumstance, or because it's who I am? Are the things you do because of circumstance, or because of who you are?
If I yell at the kids and my wife, is it because it was a busy hot day, or because I'm an arsehole? If my wife yells at the kids and me, is it because it was a busy hot day, or because she's a bitch? Obviously, some people are fundamentally incompatible, some are abusive or unfaithful, and so on. But a lot of the time it's just self-justification. "I yelled at you because I had a rough day, this is forgiveable - but you, you yelled at me because you're a bitch!"
I would suggest that a financial date night or something similar, if approached with an open mind, not seeking to justify your own misdeeds while condemning the other for theirs, can improve the chances of a successful marriage. But the basis of this must be trust, and trust requires a leap of faith. At some point you must go all in.
As well, consider that many jurisdictions will treat a couple cohabiting for a certain period as married. In many cases, the law will treat your finances as one big pot whether you like it or not. You may as well get ahead of the law and act that way anyway. Some people think that because the relationship may end some day, they should approach it with defensive wariness. I think approaching marriage with defensive wariness makes it more likely it'll end.