If Ayesha was a kafirah, then why did the Prophet (pbuh) marry her?

الحدائق الناضرة - المحقق البحراني - ج ٥ - الصفحة ١٧٩

Hadaiq al Nadirah by Shaikh Yusuf al Bahrani, Volume 5 page 179

وذلك لأنها في حياته (صلى الله عليه وآله) على ظاهر الايمان وإن ارتدت بعد موته كما ارتد ذلك الجم الغفير المجزوم بايمانهم في حياته (صلى الله عليه وآله) ومع تسليم كونها في حياته من المنافقين فالفرق ظاهر بين حالي وجوده (صلى الله عليه وآله) وموته حيث إن جملة المنافقين كانوا في وقت حياته على ظاهر الاسلام منقادين لأوامره ونواهيه ولم يحدث منهم ما يوجب الارتداد، وأما بعد موته فحيث أبدوا تلك الضغائن البدرية وأظهروا الأحقاد الجاهلية ونقضوا تلك البيعة الغديرية التي هي في ضرورتها من الشمس المضيئة فقد كشفوا ما كان مستورا من الداء الدفين وارتدوا جهارا غير منكرين ولا مستخفين كما استفاضت به أخبار الأئمة الطاهرين (عليهم السلام) فشتان ما بين الحالتين وما أبعد ما بين الوقتين، فأي عاقل بزعم أن أولئك الكفرة اللئام قد بقوا على ظاهر الاسلام حتى يستدل بهم في هذا المقام والحال أنه قد ورد عنهم عليهم الصلاة والسلام (1) " ثلاثة لا يكلمهم الله تعالى يوم القيامة ولا يزكيهم ولهم عذاب أليم:
من ادعى إمامة من الله ليست له ومن جحد إماما من الله ومن زعم أن لهما في الاسلام نصيبا "؟ نعوذ بالله من زلات الأفهام وطغيان الأقلام

Ayesha used to pose as a Muslimah during the Prophet's life, and only apostatized after his death, just like the large crowd which was upon Islam during his (pbuh) life but apostatized after his death. And with the acceptance of the fact that she was a munafiqah (hypocrite),  it is evident that there is a difference between the time when the Prophet was alive and after his death (i.e. during his life she was treated like a Muslim because she used to put up the act of being one, and the rules of Islam are based upon what is apparent. But after his death she openly rejected the leadership of Ali and waged war against him). Afterall, groups of Munafiqeen (hypocrites) used to act like Muslims during his life, obeying his orders, and nothing occurred from them during that time which would necessitate them being apostates. However, after his death they revealed their hatred which they had carried over from the war of badr and expressed the hatred akin to the days of jahilliyah. They broke the pledge of allegiance of ghadeer, which is as important as the illuminating sun. They revealed their hidden disease (of the soul) and openly apostatized (in terms of rejecting the leadership of Mola Ali), without any denial or secrecy, as reported in the ahadith of the Imams (as) which show the clear difference between the two states (i.e. posing as a Muslim and openly apostatizing) and the two times (i.e. during the Prophet's life when Ayesha and the hypocrites used to act as Muslims, and after his death when they apostatized). So would any sane person believe that these kafir lowly scums remained upon Islam and would base his arguments on them (i.e arguing that the non Shias are non najis because the Prophet in his lifetime used to treat Ayesha and the companions like Muslims while they had not yet revealed their apostasy)? Fact of the matter is that their (as) ahadith say that "Allah will not speak to and purify three people on the day of qiyamah, and for them there would be a very severe punishment. These three are: One who claimed divine imamah while not being a divinely appointed Imam, the one who rejects the divinely appointed Imam, and the one who believes that the former two people can be considered Muslims even in the least bit." We seek the refuge of Allah (swt) from the slips of the intellects and oppression by the pens (as committed by those clerics who have a soft corner for the enemies of the Prophet and his ahlulbait).