Marriage in Islam is intended to cater to multiple purposes, which include, above all, spiritual tranquility and peace, and cooperation and partnership in fulfilling this divine mandate of marriage. Islam, being a natural way of life, takes into account all of genuine human instincts whether physical, spiritual, intellectual, or emotional.
According to the clear statement of the Qur’an, tranquility and peace through a successful union is considered the primary objective of marriage. (Among His [Allah’s] signs is that He created for you spouses of your own kind in order that you may repose to them in tranquility, and He instilled in your hearts love and affection for each other; verily, in these are signs for those who reflect (on the nature of the reality)) (Ar -Rum 30:21).
Marrying a sick spouse, according to some scholars is not haram (Arabic for: prohibited according to Islamic teachings). For more precautions, the person is recommended to check with the medical channels if such sickness is transmissible or not.