The definition of atone is to make good on a past wrongdoing.(verb)
Contacting a past romantic partner and apologizing for cheating is an example of atone.
See atone in Webster's New World College Dictionary
See atone in American Heritage Dictionary 4
verb a·toned, a·ton·ing, a·tones verb, intransitive
Origin: Middle English atonen, to be reconciled
Origin: , from at one, in agreement
Origin: : at, at; see at 1
Origin: + one, one; see one.
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