Complex sentence: Minor characters constantly mistake Booth and Brennan for a romantic couple, an accusation which they consistently and vehemently deny, although they spend more and more time together outside of work and a sexual attraction between them develops.
Split into simpler sentences: Minor characters constantly mistake Booth and Brennan for a romantic couple, an accusation which they consistently and vehemently deny. Though denying a romantic relationship, they spend more and more time together outside of work and a sexual attraction between them develops.