Welcome to the forum. Great to hear about your leap into your new life and the role your fianc plays.
My take on the self-sufficient life is that it involves work, dedication, skills, good sense, enjoyment, self-responsibility, and all these things. But it need not be isolated. There is such a thing as 'voluntary interdependence' where you cooperate with neighbors for mutual benefit. We raise a lot of surplus pears, cucumbers, squash, garlic, berries, and leafy greens that we give away or trade - as well as lots of stuff we just can, freeze or put in the cellar (potatoes, corn, tomato sauces, carrots, onions, beets, pears, apples, and all). But where I live, one household may be raising a lot of free-range chickens or turkeys, another may be raising quite a few honey hives. And when you know a lot of people on organic homesteads, trading around can be natural.
You can learn from your neighbors, too. You can learn by trial and error, and there's learning from books or magazines or learning from videos. But in my opinion, best is learning from someone who will take the time to teach you (and also you can learn on the sly, by watching people who are good at something). These days, I'm helping a young man in his early 20s learn some carpentry.
Anyway, that's my little piece on interdependence.