Welcome to the forum. Thanks for your question.
We get many questions about oral sex an risks for HIV and other STDs. The bottom line is that oral sex is generally regarded as safe sex. It isn't completely risk free, but the overall chance of infection is a lot lower than for unprotected vaginal or anal sex, and the risk of some STDs is zero or very close to it (HIV, for example).
Therefore, generally STD or HIV testing isn't recommended after oral sex events unless the risk is unusually high -- for example, if you know for certain your partner was infected; or, of course, if you were to develop symptoms of your penis, such as discharge of pus or mucus, blisters, sores, or other skin problems. Without these things, I don't recommend testing, and I wouldn't do it myself if I were in your circumstance, and I would continue unprotected sex with my wife without fear of infecting her with anything. But of course nobody can give an absolute guarantee, and you are always free to visit a clinic or doctor for testing if this reassurance doesn't settle things for you.
Below are links to some other threads that go into more detail about oral sex and STD or HIV risks.
Best wishes-- HHH, MD
http://www.medhelp.org/posts/HIV---Prevention/Still-scared-of-a-possible-HIV-transmission/show/1415872
http://www.medhelp.org/posts/STDs/Oral-sex-risk---unprotected/show/1700243
http://www.medhelp.org/posts/STDs/Simple-question/show/1723730