Unfortunately, sex one had years ago can (but not likely) show up with a positive result or genital warts. Blaming each other makes no sense. The odds are always better that warts are from recent (6-12 months ago) sex but it is not impossible for the warts to appear from sex 5-10 years ago. Its just not that likely.
Pregnancy does lower a woman's immune system and some people think that a low immune system can cause the warts to appear.
When people have active (visible) warts, sex should be avoided. Or the man should wear a latex condom to reduce the chances of the warts not going away. Getting healthy (no warts) should be your and his highest objective. Both of you should see a doctor and get the warts removed.
I tried AHCC for HPV and had limited results
Then my herbalist suggested I take it with Hyperisince and HPV nosodes from Biogetica as part of their DSPL freedom cellular health kits and the results were amazing. I took it for 3 months and all my pap smears have been clear since. AHCC does help but not as much as it does when you combine it with HPV nosodes and Hyperisince which has another herb called Hypericum Mysorense