Jonathan Wignall, 56, plagued the ITV star, 47, by ringing her dozens of times a day and turning up at her television studio.
He pressed her fingerprint into her phone while she slept so he could gain access to check her messages.
Nightclub owner Wignall was jailed for three years in April 2021 after he pleaded guilty to stalking and coercive control.
Cardiff Crown Court gave him a restraining order forbidding him from contacting Ruth after a nine-year campaign of abuse.
Ruth is urging other victims to leave abusive relationships after revealing her ex got out of prison on Tuesday.
She said: “I am nervous and worried because I don’t know what the future holds for me and my family.”