Elsewhere in your letter, you mention the name of the group that has attracted your wife, and unfortunately, it is a cult that has a reputation for demanding absolute loyalty from its followers—even if it means leaving their families.
And although this group claims to base its beliefs partly on the Bible, in reality it rejects some of the Bible's most important truths. One of these is that marriage is from God, and God doesn't want you to break the vow you made when you were married. Jesus said, "Therefore what God has joined together, let man not separate" (Matthew 19:6). The Bible also says, "If a woman has a husband who is not a believer and he is willing to live with her, she must not divorce him" (1 Corinthians 7:13).
Admittedly, you face a very difficult situation. People who are attracted to cults often become convinced that they alone are right and everyone else is wrong, and they become afraid to listen to anyone outside their group. They may have been searching for God for some time and believe they've finally found Him. Only later do some of them realize their error.
My prayer, however, is not only for your wife, but also for you. Don't be deceived by this group, but turn to Jesus Christ and open your heart and life to Him. Then ask God to open your wife's eyes, as well, so that she too will discover Christ's joy and peace.