Does one who legitimizes a sin, then repents of legitimizing it, but still commits it while acknowledging its prohibition, become an unbeliever?

The one who deems every sin permissible does not become an unbeliever. Rather, only the one who deems permissible that which is known to be forbidden by necessity, such as adultery and drinking alcohol, becomes an unbeliever. Whoever commits any of these acts, deeming them permissible, is an apostate. If he repents from this permissibility, he returns to Islam. However, if he persists in the sin, its burden remains upon him, and he is considered among the disobedient Muslims.