What should be done now after learning the ruling on pre-seminal fluid (madhiy), knowing that I was previously unaware of the ruling and used to perform ablution (wudu') and pray more than one obligatory prayer with a single ablution?

If a Muslim performs ablution (wudu'), it is permissible for him to pray as many obligatory and supererogatory prayers as he wishes with that ablution, as long as his ablution is not invalidated. The emission of pre-seminal fluid (madhi) is among the things that invalidate ablution. So, if the questioner performed ablution and then saw pre-seminal fluid and prayed without performing ablution for it, her prayer is invalid, due to the Prophet's (peace and blessings be upon him) saying: "Allah does not accept the prayer of anyone of you if he passes wind until he performs ablution." Agreed upon. If she was ignorant of the ruling and did not neglect to learn, there is no sin upon her, but she must make up the prayers she performed without purification. Sheikh al-Islam Ibn Taymiyyah held the view that whoever omits a condition or pillar in prayer out of ignorance of the ruling is not required to repeat past prayers, but rather repeats only the current prayer after learning, and maintains what he has learned in the future.