Blake Griffin's ex, Brynn Cameron, claims the NBA star dumped her ONE WEEK before their wedding date because she wouldn't sign a prenup ... and then jetted to Vegas to party without her. In her lawsuit, obtained by TMZ Sports, Brynn claims the NBA star made an oral agreement with her back in 2013 that she would quit her job to raise their kids so he could focus on getting a max NBA contract, worth more than $170 mil. In exchange, Brynn says Griffin "promised explicitly that, whatever the future might hold, he would take care of [Cameron] financially and provide her a home for the rest of her life." Brynn says she and Blake were slated to tie the knot in St. Barth's on July 28, 2017 -- but one month before the wedding, he demanded she sign a prenup.