Welcome to HW. You will see that there are many people on here who are the spouse of someone with BP (I myself am the wife of someone with BP). It is quite helpful.
As for the hypersexuality, if you've read enough about BP you should know that this is a symptom. During my husband's last manic episode, I checked his phone log and saw that he called **********s on Craigslist. I was horrified because not only is he against cheating 100% (we both think you should break it off before you start to cheat) but being that he was manic I was afraid for my safety. When he finally went back on his meds, we talked about how I felt so betrayed - that he threw the marriage vows we said to each other in front of family, friends and God.
If your wife has been self medicating for years and was just recently diagnosed, she has a lot going on. Being diagnosed with BP is a very difficult thing and if she isn't on any meds, she's going to have some ups and downs. I think counseling is something you BOTH need - whether it is togther or separate. I see my own therapist because as you know, marriage is hard but throw in BP and it's a little harder, and sometimes I just need to vent.
Keep posting here but more importantly get some help for you and your wife so you can work it out and do what's best for everyone.