Praise be to Allah.
Sufis are of various kinds with various schools of thought, most of which follow innovation and deviant ways of various kinds. Some of them exceed the proper bounds to the extent of associating others with Allaah, may He be exalted, such as praying to the dead, turning to them to relieve distress and ward off calamity. Some of them follow a great deal of innovation in their deeds, in dhikr and in worship. See question no. 4983 for more information on some of the deviations of the Sufis, and question no. 34817 for information on shirk and its types.
It says in Fataawa al-Lajnah al-Daa’imah: Most of those who are called Sufis nowadays follow innovations of shirk, as well as other innovations, such as what some of them say, “Madad ya sayyid (Help, O Master)”and their calling upon the aqtaab (highest ranking awliya’ or “saints”), reciting dhikr in unison and calling upon Allaah by names that He has not called Himself, such as “Huwa Huwa (He, He)” and “Ah, ah (a contraction of the name of Allaah)”. Anyone who reads their books will notice a lot of their innovations of shirk as well as other evils. End quote.
Marriage to a Sufi woman is subject to further discussion.
1 – If she is one of those who commits shirk in belief or in deeds, such as one who believes that the awliya’ (“saints”) have knowledge of the unseen and have control over the universe, or she believes in incarnation of the divine or the unity of all things, or she devotes worship to something other than Allaah, such as du’aa’, seeking help, sacrifices or vows, then it is not permissible to marry such a woman, because she has committed major shirk – Allaah forbid.
2 – If she has not fallen into shirk, but she does some acts of innovation such as celebrating the Mawlid (Prophet’s birthday) or invented forms of dhikr, or reciting a certain number of dhikrs for which there is no basis, or a certain manner of dhikr that is not proven in sharee’ah, then it is better not to marry such a woman, because the danger of innovation is great, and the harm caused by it is severe. It is dearer to Iblees than sin, because one may repent from sin, unlike innovation, for the one who does it regards it as part of religion by means of which he may draw closer to Allaah, so how can he give it up? Moreover, marriage to a woman who follows bid’ah presents a danger to the children and to the whole family, especially if the woman speaks well or is of a good attitude, so that others may be deceived by her. Imam Maalik (may Allaah have mercy on him) said: Do not marry the people of innovation, or give your womenfolk to them in marriage, or greet them with salaam… al-Mudawwanah (1/84).
If he did not know that the woman was a follower of Sufism until he married her, then if she is of the first type that commits shirk in word and deed and belief, he should call her (to the proper way) and advise her and explain to her. If she responds, then praise be to Allaah, otherwise it is obligatory to separate from her, because it is not permissible to marry a mushrik woman or to remain in such a marriage, because Allaah says (interpretation of the meaning):
“And do not marry Al-Mushrikaat (idolatresses) till they believe (worship Allaah Alone)”
But if she is of the second type, which does some innovated actions that do not reach the extent of kufr, then each case should be examined separately – to what extent does the woman adhere or not to the innovation that she believes in, and what effect will that have on the household and the children?
He should also look at the consequences of divorcing her, and he should do that which is in the best interests of Islam in each case, and which will ward off harm or reduce it as much as possible.
May Allaah help us all to do that which He loves and which pleases Him.
And Allaah knows best.