Definitely not. For a recent example, both Bob Behnken and Doug Hurley of the first manned SpaceX Dragon crew have astronaut wives, (Megan McArthur and Karen N

Definitely not. For a recent example, both Bob Behnken and Doug Hurley of the first manned SpaceX Dragon crew have astronaut wives, (Megan McArthur and Karen Nyburg, respectively). Jan Davis and Mark Lee, a married couple, both went up in 1992 on the same flight, STS-47. (I think they actually were selected prior to being married, and got married in secret during training, but I forget the exact timeline)