I’m 36 and have been with my current girlfriend for almost 5 years now - my longest relationship yet. We live together & everything else couply, just not married. I see marriage as unnecessary pressure that has a tendency to put strain on the relationship. Right now if we’re happy together we stay, if we’re not we split. Simple. Marriage complicates it.
The only reason my partner and I got married was to make insurance and taxes easier. Otherwise, we wouldn’t have done it. Only three people were at our wedding which was in our living room.