I once worked with a man that I thought was gay. The subject never came up but I assumed he was gay. He never had a girlfriend (despite being a nice gentle man with reasonable looks) and he lived with an older man who I thought he was in a relationship with.
Turns out I had the wrong end of the stick and the first clue was when a pair of boots nearly had his eyes popping out of his head one day.
She was gorgeous but his eyes were glued firmly on the thigh high leather boots with heels so long she was almost on tippy toes.
She was in her mid 30's athletic and petite. Undeniably hot. My co worker was not gay. He couldn't hide his interest. It was so obvious it was embarrassing. Never before that and never again afterwards did I ever see the man express any sexual interest what so ever.