Lived across street from each other. Met her when I was 11 and she 13.
Played together as kids. Started dating in college. Married by 20. Stayed married 24 years. She got cancer and died at 44. Six months or so from discovery to death.

Was our time together all good? No. Bad parts for both of us included having to grow up married, basically, and not have a long period of independent self-development. That makes for the blind leading the criminally insane! Lots of stuff gets done wrong, poorly, or not at all.

It's hard to call anything particularly negative. At the end, we were engaged in disengagement, having gone so far as to have separate houses, but when she got sick, all of that went by the wayside and we were tight until she died. ("What she wants, when she wants it, no questions asked, 24/7. I have no money she can't have, no time she can't have, and will be here and her advocate until she doesn't need me anymore" was my mantra. And I did it. And would do it again. Twice. Neat woman. Powerful, smart, creative, drop dead beautiful. A little prickly! But a decent human with good and bad parts, just like the rest of us.) I promised her I'd be a neat old man, and I am working it still. I always think about her when I have to make a decision, and she's part of it. Just like the old days.

That life set the stage for the one I currently have, which also has its good and bad parts, but which I am finally better able to accept and change. Death is something that clarifies life, if you can navigate it and mine it successfully. In almost all cases, one mate is going to have to deal with being the survivor, even in the best relationships.

Would I recommend it? Most certainly not. A sober old man that I am, I would tell the 20-year old to learn who you are first, learn how to successfully live your life and rule yourself, learn what's important to you, do the dangerous things you want to do while young and not inhibited and/or responsible by/for a family, and then, when you have solidified a bit... find your mate... preferably one who has done the same thing.