your deed is on file at the county courthouse. get a copy of it. you need to show your signature is on that.
do you have a camera downstairs? if so, start photographing what you consider your possessions......photograph the entire rooms, so it will show what is in place. (i read lots of true crime books

)
look through drawers, documents that you MIGHT need.....hide them in your purse.
call every relative that might know the details of how the house was purchased and get them to write their recollections down and have them note: "per telephone conversation with Jane" and the date and time they did this......and getting the statements notarized won't hurt your case.
document the income you've made and what he has contributed.
try to relax and put yourself back to the place you were when you last saw the firebox. take your time.....go through that day in your head......
xoxoxo pat p.s. no fee for all this advice