I think that it is natural to get hopeful when you see gimmers of the old H. It's learning to be self protective once you realize it's only temporary.
I agree with Beatrice and Job. MLC is so different from a WAS. My marriage was going a long like most with no deal breaking issues. It was like a switch went off in my H. One day and he started his depression and withdrawal. I was worried about him I had no idea our marriage was entering its last year.
I think it's the shock and disbelief that makes it so much harder to accept the loss. A WAS is leaving after a period of problems in the M. Much like a long time illness eventually causing death. A MLC is like someone seemily healthy suddenly dying.
Detaching lovingly is the only way. The source of your pain is H. Let him deal with the mess he's made and give yourself space to heal
Me 52 H 44 T9 M 5 BD 12/11 H split 8/12 OW moved in 12/12 OW gone for good 6/14 We get closer again 9/14 SD 13 Me 4 Grown
Accept what is...let go of what was and have faith in what will be.