I will weigh in as someone who is about to get married, and not only discovered FIRE way before my future wife, but also was much more proactive about getting to the finish line over the past 6 years of our relationship.
Divorce scares the crap out of me.
Before our relationship got the the point where I had a good feeling we would be spending our lives together, I was already saving a healthy portion of my income, and making career choices and working hard with financial independence as a big life goal. I slowly introduced my SO to the idea of FI(RE) in 2012 while she was still in school. Not immediately on board, but not a huge spender it wasn't too difficult to get buy in. However, while I continued to put myself out there in the job market, and worked longer than desirable hours, she continued to pursue a degree in a low paying field (which she does not use, and never has), and didn't have that same fire under her ass to get her income/earning potential up.
This brings us to present time. I am earning 75-80% of our household income, and bring 80%+ of the assets to our combined NW. My income will continue to rise if I play the megacorp game, trading my soul for a retirement in my early 30's.
Getting married, while I have every intention of "forever do us part", scared the bajesus out of me. If we combine our financial picture upon marriage, and things *don't* work out a few years down the line. It could unravel a decade of working towards this goal.
Did want to point out, that we don't have kids, nor want any in the future. We split household chores/work very evenly without trying too hard. I don't think I could stomach paying alimony to someone who consciously chose low stress, low pay, work and the path of least resistance. Not to mention a division of assets.....
This brings me to a question for those who may be more knowledgeable than I........how effective would a prenup be for premarital assets in this type of situation? I'm ok earning more after marriage and those assets going 50/50.....but I've been at this since 2011, and have worked my ass off for some optionality in the future.