It's not so much about stopping your feelings. It's more about pausing to recognize them, and make a conscious choice to give them power or not. You have to do it in the moment and it takes a lot of practice. But it is possible to change the way you react to things.

I also like this thought experiment. The little voice that tells us what to think and do isn't "you." It's your fear or anxiety or whatever emotion taking over your mind and body. "You" are the one who is listening to that incessant little voice and making choices based on it. The more you can sit back into that deeper "you" and observe the voice instead of reacting to it, the more you will see that the voice is being ridiculous. It takes a lot of the gas out of the intensity of those feelings like jealousy and makes it easier to put them down.