IDEA: May not be perfect for this verse, but an idea to try for a soulmate verse (just cuz of our canon of how marks are formed)
Soulmates who meet each other when they're kids, in a small town, and everyone knows their soulmates and it's so very obvious. And everything things it's that amazing Hollywood story.
But they feel trapped by it. Like they can't be their own people. They love each other. But they want to be themselves. Not just the soulmate pair.
So they agree to part for a set number of years and not contact each other at all during that time.
But they promise to meet again and decide if they really want to try again.
See where this goes.

*found in fanfic that was criminally too short*