The epley maneuver is for something different (problems with balance) as an audiologist I should tell you to not bother with this exercise, unless prescribed by a professional. It generally won't improve hearing.

Her hearing problem could have a number of causes. She brings it up during sex, so it must be bothering her a lot... Although as a guy, I would have picked a better time to tell her my problems!

Best to have her go and see a doctor or an audiologist to sort it out.