What was Medusa love interest?

Medusa fell in love with Poseidon (she was still in human form) They decided to meet in Athena's temple and Athena found them in her temple. Athena turned Medusa and her two other sisters into the Gorgons.

There are two different myths about Medusa.

In the first myth, Medusa was a very beautiful woman who lived in the far north. She had never seen the sun, but wished to desperately. Athena denied her request to come south, though, and so Medusa accused her of being jealous of her beauty. Athena was so enraged that she cursed Medusa, removing her beauty and making her so ugly that people turned to stone when they looked at her.

In the second myth, Medusa was a priestess in Athena's temple. Her beauty was great and many men courted her. Eventually she caught the eyes of Poseidon and he attempted to "seduce" her. What he did, in fact, was rape her in Athena's temple. This was a terrible violation of a sacred place and, when Athena found out, she turned Medusa into the form we've come to recognize: half woman, half snake (or dragon) with serpents for hair and a look that turns men to stone.

So, you see, Medusa did not love anyone. Except, perhaps, herself, if you go by the first myth.