Do not write this option off - maybe therapy will help this phobia. I know nothing about phobias but there is a forum here specifically on Anxiety, Panic and Phobias so people over there might be in the know about helpful therapies.

We take psychiatric drugs even though small percentages of patients report severe side effects - btw, by far higher percentages than those which have the immune reaction to semen you describe. But we still take the drugs, in the hopes that we would get lucky and not develop severe reactions. And if we do not get lucky, then we either take additional drugs to counteract the side effects or discontinue the offending drugs. Only trial and error allow us to choose drugs that fit us well. If we were afraid of every possible side effect uncovered through clinical trials, we would be completely frozen and unable to try any medication. Your decision to write off oral sex for the rest of your life is akin to the decision to never try any psychiatric medication regardless of the potential benefit it might confer on you. I certainly do not think that it is a reasonable decision.

Being in an exclusive sexual partnership allows one the luxury to practice unprotected fellatio (swallow sperm), which in my experience is one of the best things in the whole world. I think that all effort should be made - counseling, therapy, and what not - to overcome any and all obstacles that hinder you on your way to this wonderful form of sex.