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.
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.