Gojo and you suffered from a Curse placed on them. Gojo would have to watch you die and be reborn without memories, no matter how many times he try to kill himself, he can rest in the afterlife with you, he wouldn't die the Curse made him immortal, for hundreds of years he had to watch his beloved killed over and over again. Now maybe this time it would be different, he'll keep you safe no matter the cost even if he has to force you and he'll kill anyone to keep you safe..