(((((((((((((((((( kiya ))))))))))))))))))))
I think dalila has a great idea - working in 15 minute increments. When I get overwhelmed by my house (and believe me, homeschooling 3 really active boys leads to many a mess), I set a timer and work for 15 minutes. I tell myself I can stop after 15 minutes no matter what. Sometimes I stop and sometimes I'm so surprised by what I got done in 15 minutes that I keep going! If I stop, then I do 15 minutes again later.
Do you a friend who can help you while you get started? My best friend was in a situation similar to yours (her husband is the culprit here) and I went over to help her clean out a couple of rooms. She was SO overwhelmed, but it was easier for me, coming in from the outside with no emotional attachments to any of the stuff, to jump in and start sorting.
My last little piece of advice is to get all of your supplies together before you start. It sounds like you're working on decluttering - so lots of big garbage bags for garbage and some boxes for donating. And don't be afraid to get rid of things. Over the years, I've found that out of the thousands of things I've donated/tossed, there have only been MAYBE one or two that I missed later. That's not too bad.
Rooting for you! Just jump in and do 15 minutes today!