How to stop sucking on a pacifier? Son is 1.9 years old. He used to on…

How to stop sucking on a pacifier? Son is 1.9 years old. He used to only fall asleep with it, gave it exclusively for sleep. But after one and a half years he constantly asks for the pacifier and it's been three months now that he goes everywhere with it. As soon as you take it away, an outburst starts. I don't know what's causing this and why he started asking for it so much... In general, how do you stop them from sucking on a pacifier?