In Geoff Johns’ run on the Aquaman comics earlier this decade, Mera was betrothed to Nereus before she departed from Xebel, another underwater society, to spy on Atlantis, specifically Aquaman.
Given the age difference between Amber Heard and Dolph Lundgren, it would make sense not to have the latter’s character be thrown into a love triangle with Arthur Curry.
However, Mera ended up falling in love with Arthur Curry, and when she returned to Xebel years later, Nereus was furious to learn that she’s now intimate with his enemy’s ruler.
Besides, this dynamic still allows Nereus to maintain his position as someone powerful within the DCEU’s underwater realm.