The theme of forbidden love could also be present. For example, they might come from different social classes or cultures where their relationship is not accepted, so they are forced to keep it a secret in 2010. This can lead to a lot of internal conflict and emotional turmoil for the characters in the story.
Another theme might be sacrifice. In the story, perhaps the lovers have to sacrifice their own desires and keep their relationship a secret in order to protect someone else, like a family member or a friend.