Can someone be allergic to having sex?!

male yes due to acid vaginal secretions
female yes due to the ph of the sperm
both to spermasides, or similar type of birth control.
your question was not detailed

ex-husband had to go to er after having sex with a sperisidal foam couldn't urinate for 8 hours. spermaside got into his penis and caused it to be come inflammed, ouch

you can be allergic to condoms
you can be allergic to sperm
You can be allergic to fluids in the womens vagina
but you can't really be alergic to sex it self but i guess if you were alergic to fluids and too condoms you would be screwed....or not SCREWED haha see what i did there.

Yes, when you have an allergic reaction you get lots of white lumps, because you have a uretha at the end of your penis all this white stuff comes out.

What do you think?

That's like... against the laws of nature. What would you be allergic to, the sex hormones? If that was the case you wouldn't be alive very long past puberty.

I doubt it. It will be the worst life of a person if they allergic to sex, especially guys.