Hadith In Muslim (57f) That A Believer Is Not A Believer When He Commit Sins
Such acts are a complete denial of God and his commands, therefore they are blatant violation of faith. after the act is done and man feels repentance only then he attains his state of faith. A Muslims is not technically kafir for doing such acts, still his persistence can make him a kafir in spirit, i.e, the one who believes in God but is as adamant as devil, who also believes in God but stand against him.