We're in our early 40s and have been together 20 years, married for 11. No kids, through choice.
I'd do MY marriage again, because I love my husband and he's a decent man. Although I'd set standards and expectations (around housework, the mental load and earnings) much earlier, as that has been a source of continual stress for me, and continues to be, although he's now the best he's ever been with it all.
For me, as a natural introvert, I like having "my person" to come home to, to hang out with, share news with, and hopefully enjoy his companionship as we get older (health allowing).
Without my husband, I'd be much wealthier, live a simpler lifestyle that would suit me, and have less stress. But I'd be lonelier.
Would I advise a young woman, who had the world at her feet, to get married? Not sure.