Orthodoxy teaches that sin affects us, not God because He can't be harmed in any way, nor does He need something from creation in order for Him to be whole. To the contrary, God's Holiness and Justice means that He will do everything for us, that He will sacrifice Himself for us, that He will forgive us no matter how much we sin. The choice is ours, whether we want to accept His love and repent. Otherwise, if we choose to remain in our sins, we will eventually separate ourselves from God, and He does not wish this because He wants us to have life from Him out of perfect love for us, but He would have to respect our wish.