I was on OTHforums when someone asked about the Brucas break up and I realized I've got so much to say about it.
Brooke on Peyton.
If I remember it correctly: 1] Peyton told Brooke about her feelings for Lucas 2] Brooke found out about the library kiss
Peyton telling Brooke about her feelings has a big effect on the Brucas break up. Brooke could have forgiven the library kiss, she could've chosen to believe that it was innocent, but you cannot do that if you know that Peyton has feelings for Lucas. I know in the Leyton timeline it isn't like that, but in Brooke's it was. Anyone in Brooke's place...