I know it is totally over-hyped, but have you read the Marie Kondo book? It was truly life-changing for me. I would definitely recommend it if you haven't and you want to start de-cluttering... could be an amazing GAL opportunity for you to start free and rid yourself of baggage you don't need (whether you are going to move forward with H or without him). She suggests leaving memorabilia to the very end which I definitely agree with, more so in our current sitches-- don't want to get derailed. Start with the easy stuff like clothes and bathroom and kitchen crap.
With the kids, I also think having them think through what they really need and if they have toys etc that they aren't really playing with, thinking of the kid who could play with it and how much joy it could bring to that child rather than gathering dust in their room.
You've inspired me... I'm going to set aside some time to do this over the next couple of weeks!
Me (46) H (42) M:14 T:18, D9 & D11 4/19 - 12/19: series of escalating BDs 9/20 - present: R and piecing