It is quite possible to add additional Spouses (with or without Children); and, quite easy when you know how ...
In fact, you can add as many Spouses are as required.
Just as, you can add as many Parents (ie. with DIFFERENT "Parent-Child" Relationships) to a Child (ie. individual/person) as are required.
Here are some "Knowledge Articles" in 'FamilySearch":
How do I add a spouse or partner in Family Tree?
Where it states:
You can add one or more spouses directly from your relative or ancestor's page.
How do I put spouses in order by marriage date in Family Tree?
Family Tree puts spouses in order based on the standardized marriage date. Couples with no marriage date show last.
I hope this helps.