Is it incumbent upon one who has committed unintentional killing and fasted for two consecutive months to repeat the fasting if he engaged in sexual intercourse at night during the fasting period?

A man must immediately repent with remorse and sever his unlawful relationship with the foreign woman. He is not required to repeat the two months of fasting because of what he did, as good deeds are not invalidated by sins except for apostasy from the religion.