My symptoms are pretty typical - fatigue, cognitive and memory problems, irritability, sore throat, wheezy cough etc., starting around 4 hours after ejaculating, and clearing up after 2-5 days.
Last week I saw Dr. Goldmeier in London. He prescribed an antihistamine called levocetirizine dihydrochloride (brand name Xyzal, comes in 5mg. tabs) to be taken at double dosage ie. 10mg., 4-6 hours before having sex, then repeating the dose 24 hours later and again for the following 3 days.
My symptoms were relieved by something like 80% - if I hadn't been on the lookout I might have missed them entirely: a lifechanger, after 12 years of consistently feeling ill after sex.
As a word of caution, I've only tried this once, but the effects were so distinct that I expect the same result next time.
Good luck to others for whom this also might work. It's available only on prescription.