If you always make your own coffee at home:

- pick a number of cups you may drink each day, say four.

- brew your own coffee with a drip infuser, from ground coffee.

- get a container to hold, say, 90:10 caffeinated:decaf coffee grounds. After four days, move to 80:20. Etc.

Don't exceed your daily limit. You'll be cured in ~ a month. You can do it.