My cactus died

Remember that cactus I just told you about? About two weeks ago, it dried up and died. I have no idea what happened. I followed all the instructions that I read about on the Internet, and only watered it once a month, and it imploded. I’ve never had any success with cacti. They are supposed to be easy plants to grow, but all the cacti that I’ve ever had have died, so I must be doing something wrong, they always get attacked by fungi, or just dry up. They are definitely not one of my favorite plants.