I can't think of any, I guess Thurman would have stuck to his trainer had he not passed and the same with Tyson, their relationships seemed concrete and left major heartache in their lives.
It's hard though as you only really benefit from a trainer change earlier on in your career rather than later.
Pacquiao is loyal to roach. Since they first started working together in 2001.
Hearns with steward
Floyd with his father and uncle he is either trained by one or the other.
Ali with Dundee
Canelo and Chepo
Ward and Virgil hunter
Marquez and nacho
Tim Bradley and Joel Diaz are pretty close.
Lomachenko is one if we mention current fighters - he's been coached by his father for his whole life. Chris Byrd I think was coached by his mother or father something like that for his whole career? Vitali Klitschko with Fritz Sdunek I think had the constant partnership...and yeah Hearns with Manny S, and of course Ali with AD.
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