When you use olive oil on your pasta you should always put the olive oil on your pasta after you're done cooking it.
Do not put the olive oil in the water while the pasta is cooking because the olive oil can prevent the water from boiling properly and when that happens the pasta will not cook correctly.
So always cook the pasta first and then put the olive oil on the pasta after the pasta is done cooking.
Also olive oil can also prevent the pasta sauce from sticking to the pasta as well.
But when I add my olive oil to the pasta I always do after I add the sauce and after it's done cooking.
The olive oil in the water is supposed to prevent the pasta from sticking to the pot and also prevent the water from boiling.
But from my experience of adding olive oil to the water while the pasta is cooking is that it prevents the water from boiling properly.
So wait until the pasta is done cooking, drain the water from the pasta, add your pasta sauce and then add the olive oil to the pasta if you want too.