here, I just skimmed this, but here's a study published by the academy of sciences:
"The primary question motivating this research is whether men who identify as bisexual have sexual arousal patterns that are also relatively bisexual. Results strongly confirmed that men who report attraction to both sexes are more genitally and subjectively aroused by both sexes compared with men who report that they are attracted only to one sex."https://www.pnas.org/content/117/31/18369