Rose, I can't tell you how important it is to get a DB counselor if you can swing it at all.
I can also say - I understand your libido sitch, don't know if you've hit the big M yet (my W did by 40) which makes a diff. However, you might need to address some things yourself. That could be somebody besides a coach. My W said my lack of desire drove her away - and that was a weird catch 22 sitch by itself, because I thought she was the one that didn't have any desire. Go fig.
Anyway, if you can't swing a coach - I understand the last part of MWD's audio for marriage has a part for couples to listen to. You might consider that. It's easier than going to counseling for the stubborn - and it might get you both there.
For now, you've got to DR as best you can. I so understand your pain. But for the moment you've got the advantage of communication and time.
Below are only my opinions based on what I've learned from some very good people here, who should chime in at some point.
1) if he offered to sleep in the basement, that might be a good idea. You KNOW he's not having an A? You KNOW he's not going through a MLC?
2)yes, he should begin to learn what life is like without you.
3)yup, buh-bye.
4) go dark unless it's very, very, very important. Like 911 important. Or, he says something that sounds like actual progress, in which case you can either validate, or be non-committal.
I too worked with my W, so I feel a lot of what you're going through - it's so sad that so many people have such similar stories.
Stay strong.
Me: 58 Her: 59 Kids: 0 Dog: 1 ILYBINILWY: 9/15 D Bomb: 1/11/16 (found out filed) Verified OM: 1/11/16 Moved out: 1/11/16 (thought it was temporary)