What events and or actions pushed us down the road to civil war and at what point did the war become inevitable?

Undeniably, slavery was the major cause of division in the United States at this time. The controversy began soon after the United States declared independence from England; in 1777, Vermont became the first state to ban slavery. Other Northern states, such as Massachusetts and Pennsylvania, soon adopted their own policies that sought to end slavery, whether immediately or over time. (Pennsylvania, for instance, passed a Gradual Emancipation Act, which slowly gave more freedoms to African American people over an extended period of time.) 
Another contributing factor toward the Civil War was the debate about slavery and government representation. Did slaves count as people that needed to be represented in the House of Representatives? Many southern states, though wanting to keep the institution of slavery, also wanted slaves to be counted to increase their representation. In 1787, the Three-Fifths Compromise was adopted, to try to appease all parties everyone involved in the Constitutional Convention. Under this policy, three out of five slaves counted for representation and tax purposes. This Constitutional Convention presents yet another disagreement among northern and southern states.
Many people believe that the Civil War was primarily fought to end slavery. Many are surprised to learn that President Lincoln's central concern during the war was not abolition. Though he disagreed with slavery, he believed that it was his  "sacred duty as President of the United States to preserve the Union at all costs." Though he opposed slavery and declared a consistent anti-slavery position in his presidential campaigning, he was even more concerned with the disunity and separation that the country faced after his election. Lincoln was elected as the sixteenth United States President in 1860. As more and more northern states declared slavery to be illegal, division escalated between northern and southern slave holding states. Many southerners were upset over the election of President Lincoln because of his antislavery platform. Over a period of months, several states, starting with South Carolina, seceded from the United States, starting the Confederate States of America. Lincoln's election was a significant contributing reason for their secession. 
Even after states began to leave the Union, Lincoln desired a peaceful reunification. However, this became impossible when the Confederate Army attacked Fort Sumter in April of 1861. This is considered the first major battle of the Civil War.
 
https://www.battlefields.org/learn/biographies/abraham-lincoln

https://www.history.com/topics/american-civil-war/fort-sumter