To lose the libido and what can be done to help

I am a 57 year old woman, post menopausal and have lost my libido. I still enjoy sex but do not have the drive to want sex. Does anyone know what would help in this situation. I have tried OTC, herbal and prescribed meds to no avail. My husband is very supportive and has suggested posting pictures on an adult website and we have discussed threesomes as possible remedies for our problem. Any suggestions would be greatly appreciated. Thanks curiouswoman