Hairy,
You crack me up.
Yes I agree that cosleeping was a PITA.
My oldest daughter went thru a phase where she wanted to sleep with us..she was about 2 at the time. We tried it and it drove me insane. She wanted to sleep with her forehead touching mine the whole night, like a security thing. I felt like I was suffocating!

I understand that his wife uses the kids as a shield but I don't think that the cosleeping is the real issue. They could have sex elsewhere and still cosleep with the kiddos but they'd have to really work together to set some ground rules for the kids:
Bedtime is at 8:30.
Mom and Dad will lay with you for 10 minutes while you fall asleep.
Then we get up and do our own thing and will join you when it's our bedtime.

It sounds like a whole bunch of things all mixed in together to me.
His wife won't have sex with him.
The kids have no set bedtime and take forever to get to bed.
That leaves them no time together as a couple.

Eliminating the cosleeping does not address the above issues.

GOOD LUCK Paul, you can do this. You have taken the first step and that is truly the hardest, don't you think?