Please married folk please tell me this ain't the case...
What, change?
Of course change happens.
I'm almost 40 and have been married for 13 years (and we've been together for almost 20).
In the last ten years I've learned to: ski, dive, rock climb, and backcountry hike. And while this stuff isn't my wife's thing, she's always supported me 100%.
Yes, it's really the case. Not for everyone; see the guy who replied bragging about all the physical stuff he's learned to do. However, the odds of both partners in a marriage not turning into fat couch potatoes is very small. (This happened to me: I was married, I'm like that other 40yo guy and do lots of physical stuff, my ex got fat, we got divorced.)
Be very, very, very careful who you marry, and if you're not planning on having kids, think very hard about whether you need to even bother getting married at all. It's usually not a good deal, and instead will cost you more with the IRS if you're both working and have similar incomes. IMO, the entire institution is obsolete and should be abolished.
I'm disappointed you're getting downvoted, because you make some very good points (though I'd understand that some people might think you were doing so in an inflammatory way; I choose to read it more charitably).
People change, certainly. Some change is palatable, some is not. If you're an active person and plan to be that way until the day you die, and enjoyed being active with your partner... if your partner stops being active, that can be a genuine problem if that aspect is important to you and the relationship. It may not even really be the physical acts around "being active", it could be the fundamental traits and attributes of the person that make them want to or not want to be that way, and I could see those differences ending up being irreconcilable.
It wasn't just the activeness that drove us apart; she turned into a raging right-winger.
The way I see it, people are going to change no matter what, so this idea that people need to "stick together" until they die is not only obsolete, but just plain wrong. Regular friends usually aren't life-long either, as interests change, people move, etc., so why do we expect romantic relationships to be permanent? It's crazy.
Yeah, but optimally by that point you are sleep deprived too, tired from work and children too and have job that meters to you too. These personality changes happen because circumstances you live in change.
Please married folk please tell me this ain't the case...