Polyandrous Queens -Why not?

Now, this particular thing caught my attention and upon hearing the name “Elizabeth”, Queen Elizabeth popped up in my mind. Then somehow I tried to ask myself that did she marry seven times? But soon realized that she did not, she just had one husband. This realization gave rise to yet another interesting thought in my mind as to why didn’t the queens in the royal era have multiple husbands just like their contemporary male rulers. I made my mother aware of this peculiar thought and then she began to answer my query.