First, oral STIs are uncommon, even in the most sexually active women, so it is very unlikely any of your three partners had anything to transmit to you. As a result, STIs are rare even after entirely unprotected oral sex. Second, condoms are 100% protection against infections from oral sex; brief possible contact of a partner's lips with your penile skin carries no risk either. Third, all STDs acquired by oral sex would have caused obvious symptoms that you could not have missed -- mostly within a week or so and for sure within 4 weeks. Those symptoms would include abnormal discharge from your penis, painful urination, or penile sores, indicating gonorrhea, nongonococcal urethritis (NGU) which likely is often caused by entirely normal oral bacteria, and herpes due to HSV type 1. 

Considering all these factors, I would put the chance you have any STI as well under one chance in millions. If somehow I were in your situation, I would not get tested and would be continuing unprotected sex with my wife without worry. But I'm not you, and if you remain nervous despite this reassurance, you could have a urine test for gonorrhea (which automatically also includes chlamydia, even though it's rarely if ever acquired by oral sex) and blood tests for syphilis and HIV. (There's no point in herpes testing; the chance is too low and the available blood tests are not very reliable.)

So all is well -- you really shouldn't be concerned at all. I hope this information is helpful; let me know if anything isn't clear.

HHH, MD