I'm sorry to hear you've had to live with pain for so many years. When it comes to treating fibromyalgia, each of us has to find what combination works best for us. The most effective treatment plans usually involve a combination of things including medication, complementary therapies, gentle exercise and lifestyle adjustments.
As far as medications go, opioid pain relievers are not usually the first choice of treatment for FM patients. One small study indicated that opioids are not very effective for FM pain, however, a number of FM patients who are getting relief from opioids disagree.
It's difficult to say whether 60 mg of morphine three times a day is sufficient because everyone is so different. The thing about opioids is that over time you build up a tolerance for them and need larger doses to get the same degree of pain relief. While that is one of the largest dosages I've heard of being used for FM, if you've been taking opioids for many years, it may take that much to bring you any relief.
I don't know if you've tried any of the medications approved for treating FM or if you've tried any alternative/complementary therapies like acupuncture of myofascial relief therapy, but if not, perhaps one or more of those treatments might help you get by with less of the opioid medication.
Here is an article that describes some of the most effective treatments for FM with links to more information about many of them: Coping with Fibromyalgia Pain
Since you finally have a doctor who is willing to help you, maybe together you can experiment and come up with a combination treatment plan that will truly help you. I wish you the best!