Marriage is: one man, one woman (Gen. 2:18–24) in covenant (Matt. 19:6) for life (Rom. 7:2, 3).
Recommend reading:
The Divorce Myth by J. Carl Laney
Recommended sites:
Christian Divorce and Remarriage | Joseph Webb https://www.youtube.com/channel/UCxN7-jaU4JtzOHTsUrVKCwQ/videos
Marriage Permanence https://www.youtube.com/channel/UCKIhZUhYUaLecZHNEDv0hug/videos
Permanence of Marriage Until Death | Walking by the Spirit Always https://www.youtube.com/playlist?list=PLi0i4ZYG7fW3z7Um1BjaamjNKaucpX6f4