This Levite took to himself a concubine. A concubine was a second-class wife, someone who performed marriage duties, but had no social status, no legal rights in the marriage. She is more property than spouse, as also implied by the note that he took [her] to himself.
The Levite is both her husband
(Judges 19:3) and her master
(Judges 19:27).
It does not bring back good memories for the reader. The last time the book mentioned a concubine was in the Gideon story (Judges 8:31). That concubine bore him Abimelech, a son who brought great trouble to Israel. Thus, it is not unreasonable for us to expect trouble once again.
1 In those days, when there was no king in Israel, a certain Levite was sojourning in the remote parts of the hill country of Ephraim, who took to himself a concubine from Bethlehem in Judah.