Edit: Saw you deleted your post...
Long ways to go but you're crushing it... I'm not sure your location, income, or potential equity pay-day opportunities, but your monthly overhead is quite low for the family of 5 - congrats that is so huge.
A long time ago, I used to work as a cashier at a grocery store. I did it because I was in college, but for most of my co-workers, it was their permanent 9-5. As ruthless as it sounds, in their world, these minor irrelevant/annoying day-to-day things such as a SKEW/PLU not in the system, running low on bags, or someone being slow for a cash drop became these world-shaking miserable events that could totally make or break their day. I guess what I'm trying to say is people create these boxed realities and define their own problems on what makes the day great or not. I remind myself often to "realign" what matters. The easiest route? Stop caring and take things a little less seriously. Your day will get exponentially better and your day-to-day stresses can become less important. The world is not going to stop spinning.
Obviously there is no good answer on burn out or you wouldn't be here. I personally found having a super passionate hobby helped (you can force something for you to obsess over every single day and week that is not work or even family related). Then find budget to outsource as many other things in your life as possible to make your plate tiny (e.g.: stop looking at bills for a year if your wife can wrangle solo, long-term financial plan go yolo blind with a trusted advisor, annoying chores like cleaning or maintenance pay for, etc...). You can't control it all... so just make your world as small as possible for what you can personally manage. Then of course working out and go cold-turkey on pr0n. Getting on a super strict schedule if you aren't already too can help. It sucks, but no late nights and no missed early mornings.
Change in my experience is always good, even if you are making the wrong choice. Just changing a setting on where you work from in the office or at home can make the world of difference. You could just say F that job and just do something else even if it's the same role somewhere else, and I promise you it will be 100% better. Maybe try that before blowing it all up to a less-paying job or doing a complete industry bail.
Burn out is like an injury of the mind and took me a full year to recover and "realign". The passionate young-buck mojo mindset you probably compare with is never coming back to a full 100% so get used to it and be reasonable about your injury.
Anyway, sorry for the rant. Your words got to me. I promise it will get better and easier. Best of luck and hope you see this and helps just 1%.