Unironically Chasing Amy is one of my favorite movies. Probably one of Ben Affleck's best performances. Despite some of the dated references and views on sexuality, it is a very good portrayal of bisexuality. It has a good lesson on how to deal with relationships with partners with different sexual experiences. I think people argue that the characters are "immature" but that's precisely the point. If that sounds good to you, I'd recommend watching it.