Ryan, you mentioned striving for perfection - for seeking the best that we can be and mentioned "tireless trial and error" to get there. 

Ironically, that trial and error, that endless seeking for perfection is exactly what leads so many people to engage in casual and reckless sexual experiences.  But it also is what leads people to deeply commit themselves to someone - emotionally, sexually, etc - and then realize that the relationship is not "meant to be."  This happens in both pre-marital and marital relationships.  

You are right that not everyone understands the deep connection between sex and intimacy.  There are a lot of people out there who just want the instant gratification and none of the work, and many people are hurt through that.  But I think in some ways, you also lump all kinds of premarital sexual activity together. 

There are lots of reasons committed people choose not to get married.  They may simply be rebelling against social convention, but have in their hearts the same deep and lasting level of commitment a married couple does. They may have been deeply hurt through the breakup of a marriage and/or experiencing what it is like when people hurt one another in a marriage - and refuse to enter the same institution themselves out of fear, need for healing. They may be too busy/too poor... both of which are tied to societal ideas of what it means to have a marriage ceremony, and has nothing to do with their levels of commitment for one another.  

All relationships are hard work.  

And to speak the truth, marriage really sucks sometimes.  Some days you look over at your spouse and wonder how on earth they were let out of the insane asylum.  Sometimes you wonder how on earth you were let out of the insane asylum. No marriage is perfect. No marriage is free of problems. And it doesn't matter if you get married when you are 18, 25, 50 or 85. What does matter is how committed you are to riding those storms, how much ability you have to say yes, I choose keep loving you even though you never scoop the cat poop, even though you really hurt me with what you said after dinner last night, even though I can't stand your opinion on that political issue.  A big reason I would advocate getting married later is that I'm not convinced that before the age of 25 we have that level of emotional maturity.  Some of us do, but not all. 

Sex is only one small part of marriage - and to talk about it as the only part leads too many to enter marriage to soon, and too many to give up when the spark turns to a smoldering ember.