I am most concerned about not wanting to infect my longterm female partner. I want to understand when I should test so that I can be sure nothing will affect her during future unprotected intercourse (oral and penetrative).

As your question suggests, having used a condom for vaginal intercourse makes that portion of your encounter virtually no risk.  I also agree with you that she sounds to be at low risk for having any STI, even without knowing her STI status.  

Among penetrative sexual encounters oral sex (both fellatio and cunnilingus) are those with the lowest risk for STI transmission/acquistion.  Among the STIs to be concerned about, gonorrhea is the chief concern.  Chlamydial throat infections are very uncommon and poorly transmitted.  If you had acquired penile gonorrhea from receipt of fellatio, there is about a 90% chance that you would be symptomatic with an obvious penile discharge and/or burning on urination.  On the other hand, oral gonorrhea is often asymptomatic.  To reassure yourself that you were not infected, you can test with a urine test and a throat swab (the tests typically test for both gonorrhea and chlamydia) any time more than 3-4 days following your encounter and anticipate conclusive results.  I anticipate that when you test, your tests will show that you were not infected.

I hope that this information is helpful.  EWH