My kid's mom and I divorced 8 years ago, and contrary to popular belief, it doesn't have to be a bad experience. In my experience, most people stay way too long after they know it isn't going to work. I know we did. It takes two people who are actually good for each other, not just two good people, to make a marriage worth fighting for. If you know in your heart of hearts that you don't make each other better people, then it is the courageous (and loving) decision to get on with your separate lives. In our case, after about 10 years of treading water, trying everything to make it work, 4 different counselors, etc, we separated. All four of our lives began getting better, little by little, one day at a time, right from that very first day. But enough about me, I only bring that up because I know you're hearing constant advice to "make it work" and you should know that isn't always the right answer. A good divorce is incredibly better for all parties involved than a bad marriage.
If you do end up going that route, there are definitely some best practices for putting yourself in the best financial situation going forward.
The number one most important one is that no matter what happens, the two of you will be living on the resources that the two of you generate. Before you get caught up in splitting the pie, you should both focus on making the pie as big as possible. No matter how well or poorly you are getting along, that objective is easy to agree on as long as you take the time to agree on it. There are many decisions you have to make about asset sales, taxes, alimony vs. property settlement, amount vs. duration, that affect the size of the combined stash and future stash that you are splitting. Maximize that first, then talk about how to equitably distribute it. EVERYONE gets that backwards, and it is a huge mistake.
Number two, which is actually an offshoot of number one, is that any money you give to lawyers is no longer going to either of you. That means it is always better to sort out each issue yourself than to fight it out in court. You'll find that even if you do try to fight it out in court, the court first makes you go back and try to sort it yourself, and then makes you mediate it, and then makes you arbitrate it, and after months and thousands, you find that you actually sorted it out yourself anyway. If you've spent more than 30 minutes on this website, you already know more about how to act in your own financial best interest than anyone you are likely to encounter during this grueling process, and you care about it a whole lot more than they do.
Number three - If there are issues that you just can't agree on, set them aside. Don't let one thorny issue prevent you from sorting out the other stuff. My kid's mom and I did not agree on what state to live in after our divorce. Pretty big deal, since our choices were 800 miles apart. Our approach was that we would have to continue to live where we were while we sorted that out anyway, so lets focus on custody, alimony, property settlement, etc, and save the hard one for last. Small victories build goodwill and make the larger issues easier to get through. We did spend spend too much time and money on that issue eventually (learning lesson two), but not nearly as much as we would have if we tried to tackle it first.
Lesson four - this is the most important one for you as an individual in the process. You situation in the future will be better than you probably estimate it today. The unknown is scary for you and for her. Armed with that knowledge, I recommend that you hold out for duration at the expense of volume, even when a present value calculation might lead in the opposite direction. For instance, if you have the choice of paying alimony for 10 years at what seems to be a huge amount, or lifetime for what seems more manageable, go for the 10 years. If you are receiving alimony, go for the lifetime. The reason is that, regardless of state law differences, in practice it is always easier to secure a future increase in amount based on changed financial circumstances than it is to get the duration extended. In most states, it's impossible to get the duration extended beyond the original agreement. Plus, the duration can be shorted after the fact by death, cohabitation, or remarriage of the receiver. So always go for getting it over with as fast as possible, even if that means being broke, or even going into debt for a short while.
Our family (and yes, we are still one family) is living proof that sometimes the two household, co-parenting solution is the dynamic that works best. She's a great mom, I'm a great dad, we're both great people, but we learned shortly after we got married that we were not good for each other. That made us unhappy, which compromised our ability to be good for anyone else, including our kids. Now we're both better people, and everyone else in each of our lives benefits, including each other.
No matter what you do, whether it is stay married and make it work, or get divorced and make that work, you should get on with it. When you find yourself saying things like "my marriage will end in divorce sooner or later" you are not doing either one.
Good luck figuring your situation out, and let me know if I can help.