I just wrote something about this but it seems a lot of men have a hard time wrapping their heads around it. Perhaps because it's easier and simpler to blame her for no longer being sexually interested - when that is actually a direct function of what else is going on in the relationship.

In any case (as you already know) we opened up our 20+ year marriage, not because we were having issues, but because we wanted to explore "What else." It absolutely invigorated us and forced us to talk about some of the things that were in the subtext we might not have otherwise explored. In general, I wouldn't advise couples who are having problems to do this because it's a huge paradigm shift that does bring some stresses with it, but if you are working with a therapist at the same time and keeping communication open, it could be the shake up that breathes new life into your relationship. I feel like mine is better and stronger than ever now, and know of a few other women who did the same and would agree.