Family relationships changed incorrectly

After installing the new expansion pack, my Sims’ family relationships became corrupted. My Sim was married and had a child with her husband. The game changed the relationship and now the husband is shown as her brother instead of spouse. Because of this, the family tree is broken and the game treats them as siblings even though they were previously married and had a child together.
The husband is now marked as the Sim’s brother, even though they were previously married and have a child together. I didn't use any mods or codes.