Great romance requires a choice. It's difficult to find a choice that matters, ideally it is something they already have, but are giving up. That's why all the hallmark movies work because a big city girl is giving up her career to grow cucumbers or something. Making a choice to take a job somewhere else doesn't work because it's a future thing - giving up an opportunity is not the same as giving up a realized life situation. Infidelity really works because it's a former dream, and it means giving up stability, status, comfort for the unknown.