Mrs. Kowalski was never seen in Gravity, but was mentioned by Matt Kowalski during the spacewalk of STS-157. She and Matt had been married for some time, and when Matt was in space in 1996, he would look down at Texas and imagine his wife looking up. However, during his 42 days in space, Mrs. Kowalski got romantically involved with a lawyer.
Mrs. Kowalski then took Matt's 1974 GTQ and drove off with the lawyer. Matt only found out about this when he returned from the spacewalk.
Matt later filed a divorce from Mrs. Kowalski, but was still irked by this incident for years to come.