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.
25+ years with my spouse, not married.
We’re ‘pacsed’ though which, here in France, is not like a civil wedding but merely a contract (it takes mere minutes to have it done). That ‘pacs’ helps protect the other in case something should happen to one of us since, not being officially married, we have no legal protection, no power of decision if the other was incapacitated, and no right to inherit from another at least not without having to pay a lot of taxes whereas it’s zero taxes if we’re pacsed and we’ve made a will.