Letter agreement

I need a partner to sign letter stating: that all expenses which raised from august 2021 up till now was paid by his own will and he will never asks me to refund. Also, that if our relationship will not work out he will leave in peace with no threatening approach. Also, that he doesn’t suspect me or hold responsible for disappearance of his valuable documents and That he will never file any police or court case against me. Also, that he aware by signing 3 copies of this letter and that the 3rd signed copy will be sent to my family lawyer.