situational intimacy
n. Intimate feelings that are generated by proximity or a shared situation instead of love or some other deep connection.
In September, George Sowa, a World War II bomber pilot, spent a lot of anxious hours in the waiting room of the Andrews Air Force Base hospital, where his wife was operated on for lung cancer and placed in the intensive care unit. In the situational intimacy of such places, he got to know Robert Miller, a retired military man, who was hospitalized for an irregular heartbeat and liked to escape his bed occasionally for the more companionable waiting room.
—Jean Marbella & Michael James, “The hunt for $ 7 million,” The Sun (Baltimore), February 25, 1996
1993 (earliest)
Intimacy isn't just for people in love.

Indeed, the Rev. James W. Hanna, director of the Samaritan Center of Lancaster County, finds the patterns of intimacy in all sorts of relationships, including the individual's relationship with God. . . .

He explores intimacy with one's family, one's beloved and, with some unexpected references to the Book of Job, one's God.

In addition, he explores situational intimacy — for instance, the intimacy that springs up at work, at a concert, lecture or ball game, or watching a national story unfold on television.
—Naomi Yocom, “More than Love; Hanna book expands idea of intimacy,” Lancaster New Era (Lancaster, PA), May 11, 1993