In a "polyandry" environment, wouldn't husbands be jealous of each other?

Generally no

Because marriages under this system are all walk-in marriages, and couples who do not live together can make an appointment with their wives when they come

People’s concepts in places with such a system will also be different. Just like the polygamy in the Republic of China is one’s heart. If you don’t take it personally, others won’t laugh at it.