It sounds like it's not his fault. He didn't commit adultery, he just "became unfaithful" to his wife. Big difference.
Being unfaithful to a spouse, including pornography, is adultery. The first person pronoun is used in his statement. The more salient point for the faith communities with a common theological persuasion is do they still assert all sins (past, present, and future) are forgiven when he had his conversion experience or do they reject him as a bona fide Christian. This seems a typical tragic case where a false sense of security did not acknowledge that grave sins separate one from God at the real risk of eternal darkness where there will be weeping and gnashing of teeth.