What is the ruling on ignoring thoughts and desires that cross my mind during prayer, and am I obligated to confirm the emission of pre-seminal fluid because of them?

First, we warn against obsessive whispering (waswasa). If you perform ablution, the default is that your purification is valid, and its invalidation is only confirmed by certain conviction. You are not required to search whether anything has exited from you or not. If you doubt the emission of madhy (prostatic fluid), proceed with your prayer and do not pay attention to this doubt. You must strive to repel evil thoughts. If you are certain of the emission of madhy, please refer to Fatwa no. 59304.