An Artemis love story is perhaps not one that you would expect, knowing what we do about her strict self-imposed chastity and desire to stay as far away from civilisation as possible. While Artemis was pursued by many deities, she fiercely rejected most of them - with severe consequences if 'no' wasn't enough.

But then there was Orion. A Hunter and Giant, when Orion arrives on the island of Crete and meets Artemis and her mother, Leto, a connection appears to have been made. Perhaps a shared interest in nature, or their mutual love of hunting.

Diana and Orion by Johann Heinrich Tischbein, c. 1762

In most retellings of their story, the pair are a fierce Hunter team where they spend their days deep in The Hunt, pursuing their prey, attempting to outdo each other at every turn. A friendly rivalry, perhaps one of the only friendly rivalries that Artemis ever experienced in her life.

But this is where the stories diverge.

Landscape with Diana and Orion by Nicolas Poussin, c. 1660-64

In one legend, Orion oversteps Artemis' strict boundaries and attempts to force himself upon her. Naturally, this story ends in his death.

Orion and Artemis are also main characters in a legend of Apollo. Apollo becomes jealous of the relationship between Orion and his twin sister. One day Apollo approaches Artemis and, knowing her particular pressure points, challenges her to see which of them was the superior Hunter. Of course, Artemis being Artemis, she is going to prove herself.

She asks Apollo to name the target. He points to a rock in the distance, bobbing just above the water of the lake.
She aims her bow and fires the arrow, easily hitting the target.
Except the target isn't a rock. Apollo, overjoyed, has tricked her into aiming at the head of her bathing lover, Orion.

Diana and Orion by Daniel Seiter, c. 1685
Depicts a heartbroken Diana upon the accidental death of Orion, after she has been cruelly tricked by her brother, Apollo.

In another particularly famous Orion and Artemis story, Orion allows the excitement of the chase to overcome him, and makes the mistake of boasting to Artemis and Leto that he was going to hunt and kill every creature on the Earth. Artemis becomes enraged at this threat, as for her the Hunt and the animal kingdom are sacred; and she strikes him down with an arrow.

There is also another version of this story where it is in fact Gaia that strikes Orion down after this promise - as she considers all earths animals to be her children. Gaia summons a giant scorpion to send after him, and he is brought down with the scorpion's great sting. Artemis, heartbroken, begs her father Zeus to place Orion in the sky forevermore, and you can still see him in the heavens above us now as the constellation Orion - chased for eternity by the constellation Scorpio.

There is one string that attaches all the legends of Orion and Artemis - and that is that in none do they all live happily ever after. All end in the death of Orion.

Sources
https://mythologyexplained.com/artemis-and-orion-in-greek-myths/
https://www.greekmythology.com/Myths/Mortals/Orion/orion.html