My cockatiel only bonds with one person

My caique absolutely LOVES my partner but hisses and lunges at me, and I'm the one who feeds and cleans! Anyone else deal with this? How did you build a relationship with a one-person bird?

If you're in the Beaches, check out the avian vet on Dundas St. They're amazing with cockatiel specifically.

Update: took everyone's advice and things are improving. Noodle is slowly coming around. This forum is the best.

I showed this post to my bird and they looked at me with zero remorse. They know what they're doing.