Hmmm, I hear the sound of faint alarms, perhaps much ado about nothing... However, nothing wrong with a little extra precaution when taking on major life events, especially when there is quite a bit at stake for you.
Here are my perceptions for what they are worth...If you don't mind doing all the extra work of actually selling the house you ought to get compensated for your trouble, and you should have the right to make reasonable decisions on how to proceed.
My concern for you is that you get quibbled ad nauseam over every little thing by STBX if you take on all the responsibility of repairing, replacing, sorting, staging, etc., the house in preparation for sale.
After all, he has secured his accommodations while you will have the additional burden of getting new digs. Or, conversely, you might get much tapping of the watch, why is this all taking so long? Either way, much added stress for you.
You get the responsibility while he retains the power to judge, in other words? Also, what if he has a mental breakdown during this house sale process and becomes unavailable to answer questions that may occur during negotiations for the sale?
Do the terms of the divorce allow you to make executive judgments on how the house gets sold or is there just vague acknowledgment that things must be done and accord will magically be reached?
And is it spelled out that he will continue to make his share of mortgage payments until completion of the sale? He can't have it both ways playing the mental health card. It's not unreasonable to be concerned about his ability to deal with the very stressful life event of selling a house and going through a divorce.
You know who will step into the breech if he can't deal : OW. She will be the one handling his side of the process as his agent. An unpleasant thought to contemplate but what other choice would they have?
You will be taking on a lot of extra added work on top of the jobs you are holding and you have a right to protect your mental and physical health, too. STBX has back-up in OW while you are doing all the heavy lifting. You might be just as happy to do everything yourself but that doesn't mean you work for free.
To me the logical conclusion is that you should get 70/30. Unlikely that STBX would agree to this, however the 60/40 was because you would be taking on DD, not because you were handling all the extensive work of selling the house, the fixing, the painting, the cleaning, the time off from work for paperwork. 65/35 then. Money is what you get in exchange for giving up your time.