be like ships in the night
Of two or more people, especially those who live together, to not see very much of each other; to not be in the same place at the same time very often. (A shortened version of "be like ships that pass in the night.") Ever since Georgina started managing the restaurant at night, she and I have been like ships in the night. We've had a guy renting our spare room for the last two months. We were worried it would feel crowded, but he works so much that we're like ships in the night with him.