It is not so much "... main husband ..."
The term is "Preferred" Family.
For an individual/person ...
IF, there is more than one "Couple" Relationship; THEN, in the "Family Members" Section, the relationships appear from 'Top to Bottom' in "Date" Order (and, those without an 'Event' / 'Date' at the 'Bottom')
Just under the Couple, there is a "Check" 'Box', where you select the "Preferred" Family.
Here is a "Knowledge Article" in 'FamilySearch':
How do I set the preferred spouse or parents in Family Tree?
I hope this helps.