The pope cannot change teaching
If you would cite a specific instance you would have a better argument than falsely analyzing my life which is not an effective argument
I looked it up on the internet and found a site called "Catholic Answers". It says that the church cannot change "teachings" as in doctrine. They can change ("loosen") disciplines. See site below for examples if you'd like.
I guess it depends on whether a stance on homosexality is a doctrine or a discipline. I was unable to find cite that states whether the Catholic Church categorizes their stance on homosexuality as "doctrine" or "discipline", but I would be surprised if it is considered a doctrine.
http://www.catholic.com/quickquestions/can-the-church-change-its-doctrines