You may be able to explain it in terms of being similar to food allergies, people seem to understand that more. Or you can just explain that there is a structural issue (most of us it is ) and there are things you have to do to manage the symptoms. Anyone you date should be understanding of this in this day in age. You are right, it is annoying, unfortunate and frustrating. It can get depressing and tiresome explaining but you have to do what you need to do to manage the symptoms.
GERD Moderator; Diagnosed GERD, no other medical conditions (this one is enough)