While she was sleeping
Alpha Richard was thinking about Cassie's words and he had a feeling that he might be on to something.
Just like many other Alphas and Elders, Alpha Richard is keeping an eye on Damon (and on the movements of the Dark Howlers pack), and Alpha Richard is aware that no matter how much they tried to pressure Damon, it was nearly impossible to influence him because Damon didn't expose any weakness.
The circle of people who can approach Damon is small, and he doesn't have any close family members. No matter what girls they send Damon's way, none of them kept him interested for more than one night. Well, Cassie is an exception, but she never went beyond occasional hookup.
However, if there is a girl who managed to invoke Damon's protective side, she might be someone important.