If you came here because you're under the impression that the character known as Superman - who goes by Clark Kent in his everyday life as a mild-mannered reporter for a major metropolitan newspaper - is now categorized as bisexual: he's not. Hang in here with me.
Let's start by clarifying - at this time, Clark Kent, Kal-El of Krypton, is still into women as far as the comics have indicated.* The "Superman" in question is - in current Superman comics - the young-adult son of Lois Lane and Clark Kent, one Jonathan "Jon" Kent. In the comics, as Clark Kent has had to take care of some business elsewhere, Jon Kent has been promoted from Superboy to Superman.
It happens. I don't make the rules, I just report them. But, yes, there are now two Supermans. Mens. Whatever. It's less and more complicated than who is and is not a Green Lantern.
In coming issues of Superman: Son of Kal-El, a maxi series based on current events in Superman comics, it seems our guy Jon is finding love with a male reporter. Jon Kent's sexuality is not an issue for me as a reader. He's a character reflecting both science-fantasy ideals but also a character who will be defined by many characteristics as a person which will appear in his serialized adventures hopefully for many years to come.