HPV is not like herpes. It is not only contagious during an "outbreak". Further, the warts aren't really an outbreak as they do not come and go. HPV lives in the skin so it can be contracted even with condom use.
Whether or not it is possible for a man and woman to break out at the same time from a 20-year-old exposure seems unlikely. If both parties were under a great deal of unusual stress at the same time which affected both of their immune systems, it may be possible. I would certainly be looking at alternative possibilities before I'd be accepting that as a definite, though.
In my case, I had an abnormal pap approximately 8 months from my initial contact with my husband after his affair. I knew to get tested because the OW informed him that she was in the middle of a cervical cancer issue. I knew at her age, cervical cancer likely meant HPV. I did not develop warts and the HPV resolved itself within a year. All paps since have been normal and it has been about 10 years since my first abnormal pap and subsequent colposcopy. At my initial consult with my doctor, he felt certain that the HPV would resolve itself if we did nothing because I was healthy and did not drink or smoke. He said that smoking seems to have an adverse affect on the body's ability to resolve HPV and that someone with a compromised immune system might also have issues.
My husband did develop warts within the same time frame. Because he is a smoker and drinker, he stopped drinking, cut way back on smoking, and took vitamins to boost his immune system. He also stopped taking all over-the-counter pain medications (like Advil, Tylenol, etc) as they can compromise the immune system. It took his body longer to resolve the issue but they went away on their own with no treatment within about two years of the initial outbreak. He has never had a wart since and his doctor said that, like me, his body spontaneously resolved the issue.
[This message edited by Tearsoflove at 6:09 AM, January 6th (Monday)]