Turn your mind to things that are appropriate for you to be thinking about and leave the priest alone. Your very words are "I think I know a priest who might be gay." That means that you don't know anything about this man, and it is an injustice to him for you to be entertaining thoughts that he is homosexual. In fact, entertaining such thoughts is a matter of sufficient gravity that you might want to think instead about whether or not you should go to confession (preferably to another priest, if at all possible).
__________________ "If anyone comes to me, I want to lead them to Him." --St. Edith Stein