(( Honourable mention will come next chapter because i haven't been on in so long and i'm sorry !! ))
Person A of your OTP is a royal monarch annointed at six days old. Person B, on the other hand, is heir to the throne of an opposing country. As children, they were set up to be married to form an alliance, and they do fall in love - if only opposing forces didn't keep them apart.
Plagued by visions from someone with a gift, A is told that if they remain in B's life, they will bring about B's death. Deciding to act upon their heart rather than their head, they leave on horseback, with B calling out their name, heartbroken, and breaking the alliance.
Does A ever return? Or are they separated from B forever? If they do return, does B die?
The best comment receives an honourable mention next chapter! This imagine is also based on the clip above. Skip 45 seconds in to see the scene.