Some of you guys are insanely insecure it's beyond me...
I don't know how old the woman in question is, but odds are if she is 25 or older, there is nothing under the sun your woman hasn't done unless she is just outright against doing something. What you need to do is find a woman who has a lot of experience but with not so many guys.
Remember though, if she is licking your ass and you didn't ask her too, odds are she has licked an ass before yours. An even better example is, do you really think you are the first dick she has sucked? Who cares though. Does she have good hygene? If so, than whatever. The fact that you even care about something like this screams insecurity.
Men on this site are funny. Either be single and fuck a lot of girls or pick a good girl, accept her past (even good girls have had a crazy experience or 2, but it shouldn't be excessive, if it is, she's not as good girl as you think), and be happy with her.