Drop one session at a time so your supply will decrease gradually. I can’t imagine just stopping cold turkey. How painful! Try to get him down to just morning and bedtime nursing then go from there.
I stopped cold turkey with my son. He was 1 year and 3 months. First 3 days were tough but after that he was fine. Just don’t give in
If you do it gradually you won’t be in as much pain. Your body will regulate. How I did it with my son was offer other food or drink. Drop each session slowly.