Terrance Williams is on death row for fatally beating Amos Norwood with a tire iron in Philadelphia when Williams was 18.
Defense lawyers say Norwood had been sexually abusing Williams for five years.
Widow Mamie Norwood's affidavit says she now forgives Williams after years of anger and resentment. She says his execution would violate her religious beliefs.
Her affidavit, attached to a clemency petition filed Thursday, does not address the abuse claims. Defense lawyers say she's not giving press interviews, and she does not have a listed phone number.
Williams, now 46, is also serving a life term for killing another alleged abuser when he was 17.
