Rodolphus because he probably actually loves her and because they're married. Voldemort because Bellatrix really longs for him and shes so loyal to him.
Voldemort of course. Bella hates Rodolphus. It's a wonder he wasn't suicidal after being married to Bellatrix. Nothing against Bella of course. There is obvious proof that Bella loves The Dark Lord. Look at her body language around him. She's probably tortured Rodolphus countless times and attempted to kill him madami than once!