I am seeing a lot of wandering thoughts, some seem contradictory, and it makes me wonder if you've taken the time to organize your thoughts. For instance: "I don't want to get divorce I don't want my marriage to fail. I don't want to split the family." then later: "I have no desire to save my marriage anymore."
Those are not congruent. Either you don't want to get a D, for the marriage to fail or you no longer want to save it. It as if when you typed the paragraph about not wanting to be there this weekend, your feelings had you type that you didn't want a D. Then later in your post your were talking about how you are trying to deal with your W's behavior and felt that you DID want a D. Wanting to save your marriage is congruent with not wanting a D. Not wanting to save your marriage is congruent with wanting a D. Those two cannot be mixed up. And if they are mixed up in your head you have to deal with that in IC.
However, if you pressed me for what I think? I think you do not WANT a D, but you are essentially saying you don't want to put in the work to save your marriage. That is a different thing, and it means that you are sitting down and letting the world bring to you whatever it brings whether you want it or not. And the risk you run here is 10-15-20 years from now looking back and thinking: "If I had only done this....maybe...." or "If I had behaved this way....maybe..." Take from my experience: that is not a pleasant to be in your own head! Further, your son is 1. In 12-19 years you will be answering similar questions from him. You want to be able to look him in the eye, and tell him "I did everything in my power to not get a D, but it wasn't possible." (Notice, you don't need to point the finger at your W, but let him know that it wasn't in your power to prevent.)
IH, do yourself. Your son. Your future W (whether that is your current W or a new one). Do everyone involved a huge favor and deal with this properly. And that is through finding a good IC, and dealing with all of your emotions and feelings around this. My guess is that you are a bit of a control freak. And this whole thing being so out of your control has you spinning, and it is an unnatural feeling not to be able to find a way to control it. For instance, your W wants to sell the house (the reasons do not matter). You could have made it be known that you weren't in agreement with that, but you could have finished the projects in the name of doing what was best for you. It is your house too. You stand to profit from its sale as well. I moved last year. We bought a new house. Then we prepared the old house for the market. It was a weird dynamic as I got things done around the old house it hit me that if had done many of those things before, neither one of us would probably have wanted to move! Who knows what effect finishing the projects may have had on your WAW. Maybe none. Or maybe she would have started questioning. Now you will never know.
IH, we don't beat you up here because we don't care. I don't type out a response like this because I want to see you hurting, and angry and upset. I do it because having been a guy in your shoes I know how hard all this is. It is difficult to cut through the pain, the hurt, the bitterness, the lack of control, and make decisions that are right and for the best. And so many of here, who can objectively comment on other's sitches, try to help the LBS see the forest through the trees.
Please work this out in IC. I've never heard anyone that got into therapy look back and go "wow, I really regret doing IC". However, I have many people lament that they should have done IC a long time ago. Or they should have tried it when they have not. One of the things i've learned through experience is that NOT attempting something always leaves you with regrets, it turns out to be a negative learning experience. At least attempting something, even if it fails, is always a positive learning experience.
M(53), W(54),D(19) M-23, T-25 Bomb Drop - Dec.23, 2017 Ring and Piecing since March 2018
