Is it obligatory for someone with obsessive-compulsive disorder (OCD) who experiences sexual fantasies and doubts the emission of pre-seminal fluid (madhy) during prayer to check after the prayer and repeat it, or should they disregard that due to OCD? And is someone who suffers from recurring abdominal pain and gas during prayer, sometimes forcing them to renew their ablution, considered among those with permanent excuses or not?

The questioner knows her ailment, which is obsessive whispering (waswasah), and its cure is to disregard it and pay no attention to it. So, do not interrupt your prayer merely due to a doubt about the emission of madhy (pre-seminal fluid) or wind. You are not required to inspect after prayer whether anything was emitted or not. If you are certain that wind was emitted, then your ablution and prayer are invalidated, and you must repeat your ablution. You are not considered among those with excuses unless you cannot find a time to pray with a valid state of purity, or if its emission is not controllable such that it occurs most of the time, making it difficult for you to perform prayer with a valid state of purity.