I feel for you... I have no kids, 26 years of marriage and mine is in a apartment, took a huge amount out of 401k and is looking at filing... He wants me to keep the house, a lot of overwhelming work and taxes etc like you.
Mine did not want me to know where he lived either, afraid of some drama by me. That is my guess for you too.
What I am going say this is a long process. Do you have a therapist? This has helped me so much in the last 4 years. I read a little of your situation and I really feel there is hope. I would try and talk or email him that you think selling the house is a big step and you would like to step back and both of you take some time to see if this is what you really want. Besides the market is not the greatest right now and you may not get what you need from the house. Tell him that. Don't pressure him, try and it is so hard, to act calmly. Act in control. Come up with some numbers for the taxes and insurance and try to see if he can help pay that. It is his house too. Don't panic. Staying in the house is your best bet right now.
All of the DB here tells us to leave them alone when they do this. I have broken the all the rules at one time or another. It so hard to be patient. They see us as dictators trying to run the show. My one friend put it this way, you want him to miss you not want to kill you! My therapist wants me to let him sit so he can miss me and the life we have. When they move out they can see nothing but bad. The left behind like us see only good memories. I know how you feel about the only connection you have left. In the past ( this is the3rd time he moved out) he would come and cut the grass etc. and we could reconnect. I don't know if you have grass in Texas but see if he will come over to that kind of thing to help out. I may have made a mistake in being too independent this round, I have no reasons to have him out here as he will not help out as it is not goign to be his house.