You are a very loving husband. I really agree with the other post that there is most likely something in her past, some trauma, that is causing this respose.
Is she aware of the point you are at? Have you said to her that you really need to have a loving relationship that includes sex? Would she be willing to try some things to make that happen? Or is she willing to lose you and not try anything.
The cleanses were a good idea. Would she rather lose you than try them even if she thinks they won't work?
Another thought I has was to ask her if she would try hypnotherapy to try and remember or bring to light any past traumas. This may be very difficult for her.
At this point it is up to her to try to heal this. If she is unwilling to do that, then you can't change her.