Hi Jake, Really good question. I found a few articles about epilepsy and sexual dysfunction. First you might want to start by reading this general overview from the Epilepsy Society
- Epilepsy, relationships and sex https://www.epilepsysociety.org.uk/relationships-and-sex#.Wr2R1ojwaUk

According the Epilepsy Foundation "almost a third of all men with epilepsy have difficulty achieving and maintaining an erection. Specialists called urologists offer help to men with sexual problems, including some medications that ease problems with erection."

Have you been able to talk to your doctor about this?