I don't know if there's any magic number, but if I get the impression she's promiscuous, yeah it bothers me
Not really as long as they are disease free.
I want to answer this one so am going to ignore that you have written "Guys" there:)
The very fact that they are bothered by their partners many lovers indicates that they believe the whole more "it" then more experience deal.
When the reality is your "performance" is very much dependent on the moment and your rapo with your partner. New ones are bound to hit roadblocks whereas the ones that are together for a long time know each other's needs and are better at tending to it.
Did some one call for a virgin? I thought I heard someone calling me.