The same is true for marriage, and the same is true for life. Information is knowledge, but it isn't everything. Experience isn't everything either. Information combined with experience isn't everything either.
Our brains are always trying to create balance and decrease energy expenditure. If we spent energy and effort on every single thing we encountered, we'd implode. Our brains love habit and routine, because when things are automatic like brushing our teeth, they don't require thought, which means less energy is needed, which means that energy can be used for other things.
This is helpful, but it is also a trap, because we end up operating this way a lot of the time, seeing less and less, experiencing less and less, yet assuming that the limited information and experiences that we have had are reflections of an objective and whole reality versus just being a reflection of our subjective experiences.
No one can tell you what it is going to be like to be married or to have kids unless you choose to believe them and limit your experiences according to their truths.
So, a big challenge for us humans is to accept that our brains simplify reality in order to survive, so we can focus on more important things, which means having all sorts of unconscious programs and habits that are valuable and necessary.
It also means that if we do not see this for what it is, we will be hypnotized by the illusions our brains create, shutting the doors to new experiences and embracing the unknowns in our relationships and in our lives.
Check out this amazing 10-minute TED talk by Isaac Lidsky for more on this theme: