1. What are the chances that I contracted the warts from her? or could I have been infected before and just now became visable?No way to really know. The type of HPV she apparently is diagnosed with does not typically cause visible warts, but of course she (or any partner you've been with) could have more than one HPV type. Most people never sort this question out very well.
2. If I continue to sleep with her will I get more warts? Will she develop warts?At this point you both likely share the same HPV types, and the risk of ping-ponging them back and forth is probably remote.
3. I have been married for 8 yrs and to my knowledge she has been faithful. What are the chances that she has had HPV and infected me and thus I infected this other girl? What are the chances that I will give my wife warts now that I have them?If you have warts, any recent partner likely shares the virus. Most cases never result in visible symptoms or are diagnosed.
4. What would you recommend I do for treatment?Many options available for removing warts, none universally hailed as the best. Go to http://www.ashastd.org/hpv/hpv_learn_warts.cfm#7 for more and, of course, talk with your healthcare provider to see what they might recommend.
5. Does apple cider vinegar work as treatment?Not reliable either for diagnosis or treatment.
6. What are the chances of the warts spreading or coming back if I continue to have sex with girls that are infected?See answer #2 above. Recurrences are probably pegged much more closely to your own immune response and course of treatment, rather than any issues with additional exposure to the same HPV type(s).
Hope this helps. Post again anytime.