The Witcher, 1 and 2 — $1.99 and $3.99 on Steam. If you need something with a little more action, The Witcher series will have you covered. The fantasy RPG hack-and-slash games were developed by Poland's CD Projekt RED — and both are on pretty steep discount at Steam right now. I don't believe their sale is related to the romantic holiday, but the series involves some rather adult themes.
The Novelist — $8.99. Another indie game that comes with the tagline "a game about life, family, and the choices that we make." In the game you get to be a spectral presence observing a family — including the titular "novelist." You creep on their lives, reading their thoughts, exploring their memories, and intervening in their actions. And the decisions you make influence their interpersonal relationships and the family's story. While reviews have been somewhat mixed, most laud the design, and the game is now available with customizable controls on linux.
Gone Home — $7.99. The New York Times called Gone Home "the greatest video game love story ever told," so it's an obvious pick. In the game, you play a college student going back to visit your family in the 1990s — only to discover that your parents and sister have abandoned your home. Through exploring the house, you discover more about your story and theirs.
FlapMMO — Free. If you're mourning the loss of Flappy Bird and facing a night alone, fear not: There is a massively-multiplayer online version of the game where you can experience all of the frustration in the presence of other struggling birds.