How does this get fixed
Thank you for posting in the community about your father-in-law's error.
You can correct an incorrect couple relationship at any time. Here are the steps to remove or replace an incorrect spouse.
Tip: removing or replacing an individual's records can feel intimidating. Rest assured that changes can be undone in the Latest Changes feature. It's also helpful to record the ID number so that the removed or replaced person is easy to find later on.
When you remove or replace an incorrect spouse, the parent-child relationship also changes for any children showing for the couple. If a child is linked to an incorrect parent, the incorrect spouse may continue to show in the relationship. Remove the parent-child relationship with the incorrect spouse to resolve the issue.
How do I correct parent-child relationships in Family Tree?
How do I see what changes were made about a person in Family Tree?
How do I add a family member to the pedigree in Family Tree?
How do I add or change marriage information in Family Tree?
Wishing you success.
It does not seem to work on an I-pad, not on chrome or safari
I apologize, I did not mention that you need to click the "Add Couple Relationship" before you will see the Edit pencil between Manuel and Maria. You will then be able to delete the spousal relationship, using the instructions listed above.