Stop buying it and anything that tastes like it. Don't replace it with something that tastes similar because that's only going to keep the cravings going.

Take it one day at a time. Wake up and tell yourself "today I won't eat anything sweet" and focus solely on making it through that one day.

Then wake up the next day and do it again.

When you fall off the wagon, apologize to yourself, accept you did it, and continue to avoid it. One mistake won't break anything, but saying "well I already ate a cupcake so I might as well eat five more" is absolutely what will break you down.