The two versions have interesting implications.
Cupid stems from the Latin word cupitas which means desire.
By using this word, Elizabeth attacks Ralegh's manliness and cites it as the reason why he cannot overcome Fortune. In the Petyt manuscript Elizabeth refers to virtue, not cupid, saying in lines 11 and 12 that virtue will always overcome Fortune, and that she will not be manipulated by Fortune, and further that Ralegh must not have enough virtue or manliness to overcome it himself. The word virtue makes the poet seem righteous, his love noble, while the word cupid or desire makes his love seem more lustful. These words allude to different kinds of relationships. Both virtue and desire are described as powerful and just, a combination nevertheless conquered by Fortune.