Current status
0.4.5 · openRemarriage after a spouse dies remains an acknowledged issue in 0.4.5. Adoption was added as a workaround, and should not be described as a marriage fix.
What to check in your save
Plan heirs using the family options that are available in your save. Avoid deleting a valuable campaign on the assumption that another wedding must work.
Version boundaries
This remains an acknowledged issue; an adjacent feature is not proof of a fix.
Record the installed build, selected character or building, city and action. Preserve a save before trying a destructive workaround. Prepare a useful bug report ↗