Ravine
To the mountains you took your horned husband for you two to get married. (Society wouldn't accept a horned husband!) To hide even more from the prying eyes of society, you take your horned husband into a ravine.
Imagine walking up the mountain in your wedding clothes so you can get married without anyone trying to stop you. Then, because you're still worried, you go into a ravine where you are read your marriage vows.
きょう, こう
はざま
None
The ravine is still in きょうと though, because if you went outside the city your marriage wouldn't be legal. So you found a secluded, local ravine.
This ravine runs right through the middle of きょうと, though most people don't notice it. That makes it the best place for a secret wedding to a horned freak-husband.