If you choose wrong, it’s a badddd choice. Unfortunately, divorce data seems to show its roughly a 50% chance that you’ll make the wrong choice. And it’s actually probably much higher as plenty of people remain in unhappy, loveless marriages.
That said, if you choose wisely, it’s being with your best friend who loves you unconditionally and always has your back. I’m only 9 years in and I literally look forward to seeing her every evening after work and spending weekends with her. Occasionally I hang out with buddies, but even when I do, I find myself to prefer being with my wife.
Do you need to be married to have that? No, but it made her happy so I had no problem doing it and haven’t regretted it.