I follow Buddy on Instagram, and he really did date Chelsea, unless all of their posts were fake, but it didn’t seem that way.
One thing that that struck me in the episode regarding how much of an asshole Whitney is , is that she could just not stand Buddy being in a relationship and happy. She has to cry and bring him down and start crying about how his happiness reminds her of her own unhappiness , and now he winds up comforting her - how shitty. And yes on the bench Buddy and Chelsea were being sickeningly sweet , but you know if Whitney were doing the same with some guy she wouldn’t care if Buddy was sitting there.