I would pose the question on whether "grinding it out" is really the better move for your family? When you come home, do you have energy to play with your kid? Do you have energy to enjoy your wife's company? Does being burned out impact you so that your family is really not getting the best of you, since you have nothing left for them? How does your wife feel about this opportunity for you? Is she in favor of it? How does she feel about your concerns about limited upside potential? Providing for your loved ones is a lot more than just bringing home a paycheck. Plus, it seems that you will still be operating with budget surpluses even with the lower salary.
While you mentioned that this was more of a philosophical decision into the right course of action, since this is the MMM forum, I will tell you that I really think you could benefit from a look at the expense side. Depending on what the cost of living is like in your area, it would appear that you have significant room in your budget to make reductions that will free up more than whatever reduction you are taking in salary. As a family, you are currently making $115,000/yr according to your numbers, but you are only saving $1.5-$2K a month. Assuming you both have 401Ks at work, you could get that up to $3K a month, and should still have enough left over for a comfortable life, with additional cash savings. Plus, the emotional benefits of having a smaller expense hurdle to clear every month can also be very freeing. With the additional retirement match with the new job, and a honest assessment of your current expenses, you will probably come out ahead. In addition, you can always take some of that extra time you will have freed up and apply it to pursuing income opportunities that are in line with your passions.
Life is about a lot more than just earning a lot of money, or saving a lot of money, or having the "status" of a driven career professional. It is also about the journey.
If you really sit down and think about what your goals are financially in terms of financial independence, early retirement, and in terms of your present life needs (both financial and emotional), I believe you will see that you can accomplish them without sacrificing your mental and emotional health. While a little lower salary may mean an extra few years of work until FIRE, in the grand scheme of things you may find it better to have enjoyed the journey than find yourself in your mid 40's suffering from stress related illnesses and wondering how your kid turned into a teenager already, not to mention the impact of work-related stress on a marriage.