Tony sings to Steve on a regular basis. Steve may or may not enjoy it / join in some nights.
Steve protects his damsel in distress.
Tony getting extremely angry when Steve gets killed
Then depression settles in as he grieves over his lost love
Steve’s death triggers him building weapons again, something he said he’d never do again.
After Steve was killed and he couldn’t prevent it, or considers himself too late to, he would sacrifice himself and die if it means taking down the people who shot his sheriff. So he would gladly die to take these guys down and avenge his husband Steve.