Why do the women present a greater temptation to Robert than anyone/thing
else? Why is it important that the resist them (and no I don't mean because he
will turn into a vampire)? *
From the Story “I am legend” Chapter 1

Robert was a survivor of the plague.  

Explanation:

He stayed all alone in a place which was haunted by vampires. The world outside was terrible. He was enticed by the female vampires who taunt him with their luring acts. He would peep out of the house to have a look at the vampires who assembled outside his house. But when he knew that the female vampires were trying to entice him, he didn't want to look at that and closed his eyes. He decided to read the books on his shelf to keep him diverted from the female vampires.