Roman historians were known to slander anyone they did not like. But in the case of women it was especially egregious since they were almost always described as being hypersexual. Most of their accounts were written several hundreds of years after their subject's death.
They have described Cleopatra as someone who frequents orgies, had harem of young men and that she was willing to sleep with anyone as long as they agreed to be executed in the morning. Pliny described the wife of the Emperor Claudius as secretly going to the brothel to prostitute herself and having won a competition with the most popular whore there.
They were just friends! Really, really, really close friends! And so what that they occasionally had sex—Romans were just friendly like that!
Specially with little boys!