I’ve been married for almost 23 years; call it half my life, give or take a couple of months. I only know about “today’s culture” from reading about it, and if I meet these people in Real Life, I don’t know it. (Maybe my local Walmart is full of total crazies, but they’re acting like perfectly pleasant people, at least to me.)
Depends a lot on where you live, I reckon. The old traditions still have a lot of following, but that´s not where the world is headed overall.
Also, note that the upper-crust liberal elite de facto is very conservative in their private lives, I.e. they practice a high degree of monogamy and marriage themselves. All while preaching the virtues of “non-traditional” ways to the proles.