The Guru of the woman is her husband So where is the need for her to seek the shelter of some other Guru?

No, it is not so. If it is so, she will also follow the path of hell if her husband is following the same. If the husband himself has no Spiritual knowledge, how he can be expected to give the same to his wife. Remember! He who attains Spiritual knowledge , doesn’t remain in the company of woman. He will either remain unmarried or will take to Sanyas and move out to help others after becoming Spiritually enlightened. Therefore, it is foolish to call the husband as the Guru of his wife. Still, many will not agree to it so easily.

I’ll tell you about a person in this regard. A certain lady came to me. She said that her husband didn’t allow her to come to the Ashram. I asked her the reason thereof. She said that he believed the Guru of a woman was her husband alone. I asked her to bring her husband to me. She said that he didn’t agree to it. I asked her to remain concentrated on the Naam. She said that he didn’t let her do even that much. I told her that he is not interrupting her breath and she should recite the Naam in the Breath.
At some occasion, there was a marriage ceremony in Ranjdi. Both of them happened to come there to attend the marriage. The lady asked her husband to go to the Ashram for a while. The fellow refused to oblige her saying that Sahib knew magic whereby he entangled others. However, the lady told him that there was no harm in going. It was not binding on him to get blessed with Naam. Anyhow, the fellow agreed. The lady came to inform me that her husband would be coming to me soon. When the lady signaled me about his arrival, I told him about the necessity of seeking the shelter of a Guru. I said that even the Shastras say that one can’t attain salvation without seeking the shelter of some Guru. The fellow said that a wife needn’t have a Guru. I asked him to quote the scripture. He continued to repeat his words without giving any evidence. I at once knew that I had to deal with a hard nut. I asked him if he had heard of Shiv Ji. He replied in affirmative. I asked him if he knew the name of his wife. Parvati, he replied. I asked him to tell the name of the Guru of Parvati. He replied in negative. I told him that Narad Ji was her Guru. If the wife of Shiv Ji had to seek the shelter of a Guru, what can be said about a common man. Then I asked him if he had heard of Ram. He replied in affirmative. I asked him the name of his wife. Sita, he said. I asked him the name of the Guru of Sita. Again he replied in negative. I told him that Vashishat Muni was the Guru of Sita. Ram Ji never said that he was her Guru. Even then, the fellow continued to be unrelenting.
I told him that he was talking like an dull man who lived in Delhi. His wife had a cow. She fed her family on the earnings she got from the sale of milk. One day the fellow announced that he would give the cow in charity to one who made him understand the meaning contained in the 18th chapter of the Gita. The wife protested saying how will they earn their living. He assured her that none would be able to make him understand the meaning contained in that chapter. As such, there was nothing to worry about. She said that there were many knowledgeable persons in Kashi. The fellow consoled her saying, even if someone succeeded in making him understand in a satisfactory manner, he’ll politely say that he had not understood it.
I told the fellow that his arguments were the same as
that of that fellow. The Shastras say—

'Dhayan Moolam Guru Roopam'  

Meditate on the form of Guru.
Remember! None can attain God even after worshiping many lives. The Ramayana says—

Guru Bin Bhavjal Nidhi Tarei Na Koyi,  
Hari Virinchi Shanker Sum Hoyi  

Even if one becomes great like Hari or Shiv Ji, one
can’t succeed in crossing the worldly ocean.
Shiv Ji took Brahspati as his Guru whereas Brahma
Ji took Agni ( fire ) as his Guru.

Ram Krishan Se Kau Bada, Tin Bhi To Guru Keen  
Teen Lok Ke Naika, Guru Ke Aage Adheen  

Even the Great Souls like Ram and Krishan sought the shelter of a Guru. That is to say, the Lords of the 3 Worlds had to bow before the Guru.
After studying the Sahastras one feels the necessity of seeking the shelter of a Guru but the hypocrite puts hurdles on the path.