Who is Charles "Charlo" Spencer from The Woman Who Walked Into Doors and what is their importance?

Charles "Charlo" Spencer was Paula's husband. He abused her for seventeen years before she kicked him out. As a teenager, he was a rough-edged juvenile delinquent, and Paula was initially attracted to him because of his violent reputation. Charo was a successful carpenter, but when things got harder financially, he relied on crime to pay for alcohol and family necessities. Over the course of their marriage, his sadistic cruelty came to the surface, and he seemed to be addicted to hurting Paula in any way he could.