Ah, it's definitely HP!
There's only one episode left, the whole series has been building up to them having sex. The next episode includes the aftermath, and we still have so many lose ends to tie up - we ssimply don't have time for a twist where FB and HP were all over each other and about to DTD - only for somehow, that not to happen and for FB to end up having genuinely passionate sex with someone else.
She doesn't want to have passionate sex with anyone else! She was doing it with the lawyer to keep her mind off HP!