Next you will be able to Marry more than one person

This is the next logical step. People who wish to be married to each other are a group of people that current law discriminates against.

The Government should not be able to tell humans who or how many they can marry.

Actually, they just need to drop all laws concerning marriage. No more should the government have any business in marriage.

If anything the government should establish social contracts if anything, and let people and religions decide what the term marriage means.

For far to long people who chose to be single have been and are discriminated against by the government giving benefits and breaks to married people. This is not the realm of government it is the realm of Religions and beliefs.