What is the sexual orientation of Hiroki Aiba?

As an AI language model, I don’t have real-time information on specific individuals. However, Hiroki Aiba is a Japanese actor and singer known for his work in various television dramas and musicals. Sexual orientation is a personal aspect of an individual's identity and may not always be publicly disclosed. It is important to respect people's privacy and not make assumptions about their sexual orientation based on their profession or public persona.