We know it was just a kiss. Ridge does not and would have every reason to doubt it, given how out of it Brooke was that night. And he’d been such an @sshole regarding having Deacon even show up at their house. I dunno. I have issues with the way the story is being told, but I buy Brooke’s dilemma.
(Especially combined with falling off the wagon—the idea that Deacon’s presence in her life contributed to that, when unbeknownst to her, her drink was spiked. Again, there’s a lot there that makes me go uhhh, but the emotional drama I don’t have a problem with, aside from the repetitive nature of the scenes, which is a global problem on B&B.)