Is it permissible to wash clothes suspected of being stained by prostatic fluid – with the concern of subsequently soiling bedding – along with other clothes for purification, especially given the constant doubt regarding the discharge of prostatic fluid for the most trivial reasons?

It is clear that the questioner has not yet rid herself of whispers (waswas), and the cure for this is to turn away from these whispers and thoughts, as they are from Satan. There was no need for her to perform ghusl or istinja' upon seeing that thing as long as she doubted whether it was madhy (prostatic fluid). Whenever she doubts the exit of madhy, she should not pay attention to this doubt, and she should build upon the certain original principle, which is that nothing has exited. She should not rule that something has exited except with absolute certainty.