Is there a moral standard?

There are many different cultures in the world. With these cultures comes different views on life and how to respect it. These varying views inevitably lead to fighting over what is right and what is wrong. This is seen in many wars, that the wars are started from differing opinion, often when wars over religion break out. In Things Fall Apart we see the clashing of cultural beliefs, Okonkwo's culture let men marry multiple women while in our culture that is frowned upon. Also in Things Fall Apart Okonkwo hangs himself and those of his tribe cannot touch him because of their beliefs, however the outsiders are asked to do take him down since they do not have the same morals.
This is not just seen in literature, Inuits allow men to have multiple wives, but the wives can choose to leave, therefore no true commitment is made with marriage in their culture. Also Inuit's only keep the elderly while they can still contribute, as well as killing babies are allowed as long as it is discrete. This goes against what we consider to be correct. Which leads to the question of is there a universal truth in ethics? This is discussed in the article The Challenge of Cultural Relativism by James Rachels. I believe there is no ultimate moral that is actually correct. This is because of how there are so many varying opinions between people not to mention their cultures.
The greatest example of cultural differences is when wars break out. The Vietnam war was fought because of a simple disagreement in political issues, while the Civil war was fought over political issues on slavery. Before the 1860's slavery was common in the United States, but today it has been outlawed. This is an example of how there is no set standard of morals because morals are brought by nurture instead of nature. I believe slavery is wrong but there is a possibility had I been raised in an environment that owning slaves was common, there is no telling if I would have the same opinion. Morals are created by humankind to create a sort of order in a very chaotic world, and because of this there will never be a moral standard.