Pruning a Monstera leaf
A leaf stalk and the main vine are different parts.

What to look for
Find the leaf you intend to remove and trace its stalk all the way to its own attachment. Identify the main stem, nearby buds and aerial roots; a crowded plant can make these easy to confuse.
What to do
If the leaf really needs removal, cut its stalk near the base without nicking the main stem or neighboring growth. Keep healthy leaves and aerial roots unless there is a specific reason to remove them.