They betrayed her and broke her heart in immeasurable ways before, but knowing she has since grown to trust them again won't stop Bill (Don Diamont) and Brooke (Katherine Kelly Lang) from giving in to temptation yet again on The Bold and the Beautiful.

Brooke Begins Work At Spencer

The two once before broke up Bill's marriage to Katie, but things eventually worked back out with Bill and Katie remarrying and Katie forgiving her sister. Everyone seemed to move on from it until Katie offered Brooke a job at Spencer--and Brooke admitted to Bill that she was still in love with him. Since then, Bill has been thinking about their past too. And now, a moment alone together in his office will result in steamy passion.

"What are we doing?" a breathless Brooke asks Bill in a preview clip for the Thursday, January 14 episode.

Liam Makes A Shocking And Unexpected Decision About His Future With Steffy 

Meanwhile, Katie is not only blinded by her trust for them both, she is clueless that they've already betrayed her and is even talking to Rick (Jacob Young) about how she wants them all to be a happy family again. And even though he and others have expressed concerns about the situation, Katie will still choose to believe the best in both of them.

"Given everything that's happened with you guys personally, it could be complicated," Rick says in the clip. "You're not concerned?"

"I just want us to be able to share everything," Katie replies.

The Bold and the Beautiful airs Monday-Friday at 1:30 p.m. on CBS.

Tags: The Bold and the Beautiful CBS Soap Operas