All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
First of all, it should be mentioned that watching pornographic films is a very serious matter and this is most predominantly the main reason why your wife is attracted to women. There is no doubt that this is abnormal and it contradicts the desires of the people who have a sound Fitrah (natural disposition upon which Allaah created mankind). Indeed you did well by repenting from seeing such films and you should eradicate this evil from your home.
Firstly, you should advise your wife in a nice and soft manner and clarify to her that this matter is forbidden and very dangerous for her and perhaps for the entire family because sins may be the reason for many calamities. Allaah Says (what means): {And whatever strikes you of disaster — it is for what your hands have earned; but He pardons much.}[Quran 42:30]
Secondly, you should prevent your wife from watching such films and keep away from her all the means that may be helpful to her in this regard. This may help her to repent and you should also remind her to be honest and sincere with Allaah in willing to repent from such sin. If she is sincere, Allaah will enable her and guide her to repent. Thirdly, your wife should earnestly supplicate Allaah and remember that she will stand before Him and He will judge her about every small and big matter.
For more benefit, please refer to Fataawa 90562 and 89844.
On the other hand, we do not advise you to hasten to divorce her especially that she observes the prayer and wears Hijjaab as you mentioned in the question. Rather, you should continue to advise her and endeavour to reform her. It is most likely that she will take heed and become righteous.
If this is achieved, then all perfect praise be to Allaah, but if she insists on that condition, then it might be better to divorce her because there is no good in keeping marital relationships with a woman who insists on watching such films as it is not safe that this will lead her to harm your honour (by having illicit relations).
For more benefit, please refer to Fataawa 86547 and 81381.
Allaah Knows best.