Is the fluid that is discharged upon feeling lust, joy, or hearing good news the impure pre-seminal fluid (madhiy) which necessitates ablution? And what should a woman do if its discharge occurs frequently outside the home, causing her to lose her ablution and her clothes to become impure?

If your doubt is merely a whisper (waswasa), then disregard it. When in doubt about the emission of madhy (pre-seminal fluid), the original state remains, which is the preservation of purity. There is no need to investigate unless there is certain conviction of its emission. The fluid that exits without desire is vaginal discharge (rutubat al-farj), which is pure but invalidates wudu. If you are certain of the emission of madhy, you are required to perform istinja' (washing the private parts), wudu, and sprinkle water on your clothes. If it is difficult to remove the impurity and you fear the prayer time will expire, you should perform wudu and pray, and the impurity that cannot be removed is pardoned.