Alice and Zeke have known and loved each other for a very long time.
Alternatively: Alice and Zeke know each other better than most married couples, yet in fanon they don't have any strong feelings about each other one way or the other.
Alice and Zeke, despite barely even knowing each other, become bitter enemies the second their eyes meet, swept up in the emotional roller coaster of hate at first sight.
Alice meets Zeke, and they instantly hit it off as friends.
Alice likes guy who are a lot like Zeke, and vice-versa. It's obvious they'd be perfect for each other if only either of them knew that the other existed... And they're both going to the same place today! ...Except by the time Zoe gets there, Alice is gone, and both return home alone, yet again.
Only to become a couple not too much later.
While they've yet to meet in person, it turns out they've had an online relationship for quite some time now... And are starting to think about meeting face to face.
Alice and Zeke randomly pass on the street and pull each other in for a deep, passionate kiss, before going their separate ways like nothing ever happened. When asked who it was she'd just been making out with, Alice replies that she has no idea.
Zig Zagged: Depending on the continuity, Alice and Zeke are either inseparable lovers, total strangers, or something in between. Fanon portrayal of their relationship varies just as wildly.
Averted: Alice and Zeke are not lovers in this fic, just casual acquaintances, people who have never even heard of one another, just friends, or mortal enemies.
Defied: Alice and Zeke will only date people they are already friends with.
Discussed: "Wait...they've barely said two words to one another!"
Conversed: "At least they're from the same universe."
Things could get awkward (and possibly dramatic), considering that they don't even know each other. And what of compatibility? Being in the same place at the same time is not the same thing as being compatible.
Alternatively: Their first meeting has all the awkwardness and uncertainty of a blind date.
Reconstructed: But somehow, they respect each other's differences, and realize they do have stuff in common. Pretty soon, their relationship evolves and gets stronger every day.
Played For Laughs: Alice and Zeke are paired up Just for Fun, even though they have nothing in common and have never spoken to one another.
Played For Drama: Alice and Zeke's differences outweigh the commonalities, and the relationship turns sour.