One that commands armies in nine languages?

Caesar was a notorious philanderer who more or less had his pick of women wherever he went. His affair with Cleopatra, however, was unusually enduring and powerful. I doubt she fucked better than every noblewoman and prostitute in Rome (which, considering Caesar's reputation, he may very well have all tried). More likely is the combination of circumstance and Cleopatra's own sophisticated and educated outlook.

Caesar was, famously, a great appreciator of the humanities, with even noted enemies like Cicero praising his genuine love of literature and intellectual pursuits, and he had a vast collection of art from across the world, even before he met Cleopatra. Roman society, especially during the Mid and Late Republic, could be a bit... ambivalent about artistic interests like that. On one hand, civilization - Romans very much appreciated the work of specialist skills and knowledge. On the other hand, shouldn't you be doing something PRACTICAL, senator?

But Cleopatra is not only Graeco-Egyptian (the Ptolemies were mostly Greek, but Cleopatra took great efforts to identify herself with the Egyptian people, including being the first Ptolemaic ruler to actually fucking speak Egyptian), which means she has a somewhat... broader-minded view of art, but also a queen. She is used to being able to enjoy and appreciate refined things. On top of that, she was quite famously cultured even by the standards of royalty, and intelligent.

Caesar was in his early 50s at the time, but had only just started going bald. Caesar, who was famously handsome and vain, did not take this well. So this guy who has spent most of his life surrounded by UTTER PHILISTINES, or at least men who largely do not appreciate art on the same level he does, meets a young, beautiful, powerful woman who is (apparently) deeply interested in him and shares his interests on a similar level, and at a time in his life when he's beginning to feel the weight of age. Maybe it should be no surprise that he took to her exceptionally well, but it's definitely more than just being good in the sack!