I have a sad confession to make: I’ve seen “Phantom of the Opera.” Even worse: I was there on January 26, 1988, when this Andrew Lloyd Webber concoction opened at the Majestic Theater on Broadway. I even attended the party at the Beacon Theater afterwards. I’ve only been back to the Majestic one time since. What can I say? I was in love and the object of my affection wanted to see the swinging chandelier. There was lots of love again this weekend at the theater, as the faithful gathered to see a special performance of the musical to mark its 25th anniversary on Broadway.