I remember one time I couldn't sleep so I was thinking about ST characters sexualities and I pretty much decided for myself that I think mostly everyone is straight except for Will (gay), Mike (bi), Max (bi), Lucas (bi), El (doesn't really understand the concept of labels, you love who you love), Robin (lesbian), Vickie (bi), Steve (bi-curious), and Eddie (bi) [I don't really like Eddie and this is not about st*ddie, I just think him not being straight supports his character arc alot]. I think other characters (Joyce [pan], Jonathan [bi], Nancy [bi], etc) have experienced mild attraction to their same gender, but they simply opt to ignore it and stick to what's "normal" because, hey, who doesn’t think that the same gender is kinndda pretty kiiinnda hot every now and then.
But I really got to thinking about Jonathan, because I do love stonathan. And I like the concept of jargyle. But I think Jonathan being straight ("normal") is important to his character and connection to Will. What I was really thinking about was their talk in the pizza shop. It would have been so much different of Jonathan was bi, if he understood Will. His acceptance would have been different. It would have been Jonathan accepting Will because he understands. Don't get me wrong, thats GREAT, it's wonderful and it would show an amazing vonnection between the two of them, fortifying their brotherly bond. But it wasn't like that. It was Jonathan accepting Will for who he was, for being different. It was Jonathan not entirely understanding it, but knowing for a fact that nothing wpuld change how he saw Will. Not only is thay important to Jonathan, but it's important to Will. It's important for Will to see that, while he's relieved hate and backlash his whole life, his brother doesn't see him any differently. His brother who's (sort of) normal, who doesn't really understand, who could turn and be like anyone else, accepts him and loves him.
So yes, I love bisexual Jonathan. I love stonathan. I like jargyle. But more than anything, I like straight Jonathan.