"The stalker had been to our house many times and ultimately came to my children's school and was arrested. There's a lot of crazy, weird people out there. It's an ugly world. (It) gave me a stronger sense of feeling protective about my family," he said.
Steven Burky was arrested for harassing Garner and violating a restraining order in December 2009 after which he was placed in a mental health hospital and ordered to stay away from her and her three children, Violet, six, Seraphina, three, and baby Samuel, seven-months-old for 10 years.
Affleck isn't the first high profile actor to admit he keeps guns close to hand.
Brad Pitt previously said that he doesn't feel safe without a gun nearby to keep his wife Angelina Jolie and their six young children safe.