Warts 9 years ago have come back

I know that it is likely that your body clears genital warts in 2 years, but I have had an outbreak 9 years after my first ... and in the last 9 years the only person I have been with has been my wife.  

I am 100% sure she has not played around.

Is this possible?  I have just lost my job (got a new one though) so things have been quite stressful...

[jsmt1000]

Warts can be cleared but HPV remains latent in the body. Every person is different than each other and human immune system is such a complicated mechanism; You can never know when and how the latent virus is activated. Yet, stress is a good trigger for HPV re-activation.
As you had cleared the warts in the past, I am sure your body will do the same again and this time quicker.