A couple quick thoughts-- first, definitely talk to a lawyer. You can usually get a free consultation. Someone here suggesting scheduling free consults with the top three divorce lawyers in town, because once they've talked to you, even if you don't end up working with them, your W can't hire them. For me, having those conversations really helped ease a lot of my financial fears around D, and at least let me understand my rights. For instance, even though the house is your W's property as an inheritance, depending on the laws of your state you may very well have rights to half of the equity it gained since her mom passed. In any case, getting a sense of what your finances will look like if you S or D will help. Knowledge is power. If you decide to MO, this way you'll know what you can afford and be in a better position to map out your options.
Second, I can't stress enough how important sleep is, and I feel like figuring out how to get a good night's sleep is a critical first step to helping you figure out your path forward. A few ideas-- if you don't want to leave the MBR, go to bed really early so you can get to sleep before she gets there. Try OTC sleeping pills, a warm bath, melatonin, a glass of wine or 5-HTP (5-HTP has helped me a ton with sleep and also mood.) Tell her you're really uncomfortable sleeping in the same bed as her given what is going on and ask her to move to the office. (Hey, maybe she'll say no, but she's your W and no matter who the house belongs to, she's the one who is having an A and she should have enough respect for you to let you sleep in peace.) Move to the office yourself but go get a foam mattress topper or something to help you sleep a bit better. Go to a hotel for a couple of nights and order room service and take baths and SLEEP.
"What is best for my kids is best for me" Amor Fati Link to quotes: https://www.divorcebusting.com/forums/ubbthreads.php?ubb=showflat&Number=2879712
