How does one ensure that prostatic fluid (madhy) has stopped, and does one repeat the prayers performed after seeing the prostatic fluid stop, only to later find more prostatic fluid? Is it permissible to adopt the view that prostatic fluid is pure, for the sake of ease?

A Muslim must repel and get rid of obsessive whispers (waswas). As for madhy (pre-seminal fluid), it is impure according to the majority of scholars. The Prophet’s (peace be upon him) command to wash the penis from it is clear evidence of its impurity, and some scholars have reported a consensus on its impurity. The Lawgiver has made its purification lenient, so sprinkling water on clothes is sufficient. If you are certain that madhy has exited, you must clean yourself (istinaj) from it, sprinkle water on whatever parts of your clothes it has touched, and perform ablution (wudu). If you are in doubt, you are not required to investigate. There is no need to squeeze the penis, as this increases waswas. If you are unsure about the time madhy exited, attribute it to the nearest time it is likely to have exited. It is obligatory to avoid being alone with your fiancée and to avoid looking at her or speaking to her with suspicion, because she is a non-mahram.