When To Discontionue Estrogen Shots In Endometriosis Case?

I am 56 years old, I have had a TOTAL complete histerectomy in my early 20 s. I had a severe case of endometriosis. I had one child, after he was born, it happened. For several years my gynocologist gave them to me once a month, then, after a while, she showed my husband how to give the estrogen shots, he does a fantastic job. Now that I am older, should I stop taking them? We are still VERY active with our sexual life.