Welcome to the forum. Thanks for your question.
My main advice is that you focus your thinking so that you don't conflate a sexual experience causing guilt or anxiety and the HIV or other STD risks that may have resulted. The aren't the same. Deal with the former as you need to, but there simply are no disease/infection risks from the event you have described. Even without a condom, I would advise you were at no meaningful risk -- for the reasons detailed in the thread linked below. With a condom, there is no chance of having caught HIV and no testing is necessary. If I were in your situation, I would not get tested and would continue unprotected sex with my wife without the least concern I could infect her with HIV or any STD on account of that event.
http://www.medhelp.org/posts/show/1922236
That said, I'm not you. If you decide to be tested, I would advise against a DNA test. Such tests are quite reliable at 7+ days after exposure, but not perfect; you would still need an HIV antibody test at the one month mark to have a definitive result. You can get the same definitive reassurance with a duo test (for both HIV antibody and p24 antigen) 4 weeks after exposure; or a stand-alone antibody blood test at 6-8 weeks. Here is a second thread that goes into detail about test reliability at various intervals after exposure.
http://www.medhelp.org/posts/show/1704700
I hope this information has been helpful. Best wishes-- HHH, MD