Equal rights for long term partners( heterolsexual)

Why is it that gay people were given rights just as married but long term partners have no rights although many have been together longer than some married people?

I would suggest this would be a popular law.

Why is this idea important?

Why is it that gay people were given rights just as married but long term partners have no rights although many have been together longer than some married people?

I would suggest this would be a popular law.