Deejo

I am sorry for the direction things have taken AZMOM. In my case, there has been very little positive movement.

I couldn't help but notice your first sentence;"Our marriage is slipping away, and I had a great plan to save it."

That sums up the course I attempted to take over the last three years. The reason it won't, and can't work, is that both sides need to be aware of, and implementing the plan. If it is 'I' and not 'we', it is destined to lead to further frustration.

I want to see relationships work, I truly do. I want my marriage to work - but it isn't. We don't despise each other, we don't demean one another, we don't fight in front of the kids - but there is nothing going on to improve the circumstances. I am at the point where I see no value in working on the relationship, if it is apparent that my partner is not willing to make the same investment.
I have no idea how us splitting up might work out, but I have come to terms with the fact that I am not ok with staying in a marriage that will only continue to deteriorate into open disrespect, cruelty, and negativity.

I don't know what you mean by 'doing something stupid'? Separating? Having an affair? I have considered both of those options as well - and at this stage of the game, I consider neither one as stupid.
If you mean that you are uncertain of your emotions, that is another matter. Think things through, and don't put what option is best for you at the bottom of that list, instead put it at the top.