Laurie: Your sitch and mine have some similarities, albeit with the genders reversed. In fact, I just had yet another conversation with my W, with her insisting that sex is not a necessary ingredient to a marriage, and me insisting the opposite.
Advice? You're not going to get any overnight fixes. You have to do the hard work. Likely, you will find that you have contributed to the problems in your relationship.
One thought: why ask him to move to the guest room? Why not just move there yourself?