The myth of Cupid and Psyche was told by Apuleius (a Roman writer who lived in 125-170 aC), in his book "Metamorphoses or the Golden Ass", that's why the name of the characters are Latin (when in fact they should have been "Eros and Psyche"). It is a beautiful, romantic story... but I can't refrain from making some comments on the Cupid and Psyche story, you'll find them in red.
Psyche was the youngest of the three daughters of a king. She was so beautiful, that people began to worship her, instead of Venus (in Greek, Aphrodite), the goddess of love. Her elder sisters got married, but no one would dare marry Psyche, because of her divine beauty.
Her parents consulted an oracle about the possibility that their daughter might get married, but Venus, who wanted vengeance, inspired the oracle to tell Psyche that she was going to marry a horrible monster. Having lost all hope of ever getting married, Psyche told her parents to leave her on a mountain, where the monster would come and take her, just like the oracle had said.
You probably remember that Venus was very jealous. Her beautiful face and body didn't match a beautiful heart.
But when Psyche was left alone, the gentle Zephyr came and took her to a beautiful valley, where she saw a wonderful garden. She entered the garden and voices of invisible servants welcomed her.
When night came, her husband came next to her, and the same happened every night. But Psyche never managed to see him. She could only hear his voice and, during the day, the voices of her servants. In the morning, her husband (none but Cupid himself) would wake up at dawn and leave, while she was still asleep.
Her life was almost happy, and yet Psyche felt very lonely, as she couldn't see anyone around her, and especially her husband. So she told him that she missed her sisters and she wanted to see them. He tried to convince her it wasn't a good idea, but she insisted until he agreed.
So Zephyr went to the top of the mountain and carried her sisters to the enchanted palace where Cupid and Psyche lived. They were amazed by what they saw: the beautiful palace, the riches, the invisible servants. They asked Psyche what her husband looked like, and she said he was a beautiful young man who liked to go hunting. After they spoke a while, Psyche gave them a lot of gold, silver and jewels, and Zephyrus took them back to their home.
Needless to say, the two sisters were yellow with envy: how comes their parents married them to older men, to whom they are like servants, while Psyche was so lucky to have a young, handsome and rich husband?
Cupid and Psyche had a long conversation about her sisters. He warned her that they would try to destroy their happiness. He told her she should never try to see who he was, because if she managed to do that, it would also be the last time she saw him. Cupid also told her that, if she doesn't see him, the baby she was pregnant with would be a god, but if she saw him, the baby would become a mortal. In the end she cried and embraced him and asked him to let her see her sisters again. Cupid and Psyche were so much in love, that he agreed.
When the sisters came the next time, they asked again about her husband. This time, Psyche told them he was a middle aged merchant. The two sisters understood she never saw him and told her that he probably was a monster, a horrible snake, just like the oracle had told her. And when the baby is born, the monster will devour both mother and child.
Psyche thought about how her husband forbade her to see him, because it would be the last time she saw him, and believed her sisters. So she prepared an oil lamp and a knife and hid them under the bed.
She waited until her husband fell asleep. Then she lit the lamp and took the knife to kill the horrible monster. But what she saw left her breathless: a beautiful winged god was sleeping in her bed. She understood her husband was Cupid, the god of love himself. For a while she admired his beauty, then she wanted to embrace him and, in doing that, the oil from the lamp spilled on his shoulder and burned him. Cupid woke up and fled away, but Psyche managed to cling to him. After a while she was too weary, so she fell to the ground. Cupid followed her and asked her, "Why do you want to kill me? Wasn't I gentle with you? My mother told me to inspire you love for the most hideous creature on earth, but I wouldn't listen. You'll be punished enough from my absence."
Psyche kept thinking, "Was this the end of the beautiful marriage of Cupid and Psyche?" She was so desperate, that she threw herself into a river, but the waters took her to the bank, where god Pan told her to never try to commit suicide again.
The poor girl wandered until she arrived into her older sister's town. When they met, Psyche told her what happened and added that Cupid had declared he would marry Psyche's sister. As soon as she heard that, her sister ran to the mountain and called Zephyrus to take her to Cupid's palace, and then she threw herself into the abyss. This time, the gentle wind didn't come to carry her, so she fell on the rocks and died.
After that, Psyche went to the country where her second sister lived, and told her the same thing. The second sister went to the mountain and threw herself headlong into the valley, but the wind didn't come to carry her and she died just like the other sister.
In the meantime, the Seagull went to look for Venus and told her about what had happened to Cupid and Psyche. The goddess went home immediately and started to yell at him: "Why haven't you listened to me? Why have you got married? I'm going to have another child, or I'll adopt someone and put him in your place. You are a disgrace for your parents."
If you ask me, this is the typical behaviour of a jealous and possessive mother, who wouldn't accept the fact that her child grew up and can decide for himself whom to marry. On the other hand, Cupid had chosen a very beautiful girl, who represented Venus' "competition", one reason more for her to disagree. A married son also meant she was growing old - well, that's something that even an immortal goddess can't easily accept!