I wouldn't sail this ship if I were you
1. One or the other of you had taken an inconveniently binding vow of chastity.
2. You kissed on the understanding that one of you would turn into something else, but nothing happened.
3. You kissed on the understanding that neither of you would turn into something else, but one of you did.
3. The one time you managed to both exist at the same point in time, you were haunting a weevil, they were personifying an unusual shade of green, and you were both travelling in different temporal directions.
4. You had the kind of love that could have smashed universes, stopped time, lit the sky on fire. Other inhabitants of your universe were perhaps understandably not on board with your relationship and eventually managed to split you up.
5. You realised that you were actually in love with the idea of love itself. The idea of love refused to return your phone calls and floated the idea of a restraining order.
6. You were in love with a teacher, guardian angel, god, anthropomorphic personification or other professional superior, and all concerned felt that a relationship was probably a breach of ethics.
7. You were waiting for them to make the first move. They were waiting for you to make the first move.
8. For some reason having to do with mystical woo stuff, you were unable to fuck without causing some kind of apocalypse.
9. One or both of you were already in a monogamous relationship with someone who was engaged in saving a country, continent, planet or other geographical entity, and whose work would be put in jeopardy by emotional upset.
10. You were a bee. They were a bee. When you tried to bee together you were shut down by the bug police for excessive buzzing.
11. You swore that you would die for them and then you did.
12. You just weren’t that into each other.