Was Hannibal really gay or bisexual, is there any concrete evidence ?

To be honest, I only watched the series, I didn't read the books or see the dozens of films that were made, including the classic Silence of the Lambs. I watched the entire series twice, and I always thought he was a psychopath who had no feelings and didn't really care about anyone, just Will But, in the books or even in the movies, is there any evidence that makes it clear about his sexuality? I know there are a lot of fanfics spread around the internet about this, but is there anything real behind it?