I know there is a bit of a divide in the amount of sexual partners that's "acceptable" for a woman. Some say none, some say between 3-8, some say just less than you, some don't care. To each their own, a woman's number count doesn't really matter to me, they'll all lie anyways. Personally, I don't mind women who have experience and can give good sex, I've taken virginities and it was always a bad decision that wasn't fun.
But if you ever, and I mean ever, find out that she did something with an ex that she refuses to do with you, drop her. Drop her fast and drop her hard. This goes from giving it up on X number of dates, to certain sexual acts that you want to do, to threesomes, to the frequency of sex. It is not only the #1 sign of being on the losing end of the AF/BB relationship, but it screams "Oh, well I felt I needed to impress and be good to them, but you seem easy enough that I don't need to put in effort." Do yourself a favor and move on to a woman who sees you as equal or better to the men who used to fuck her. Don't settle for being second best.
For the women who may be getting furious reading this, just imagine what it was like if you knew your boyfriend was rich. Imagine that he always brought his ex's out on really nice vacations, nice house, bought them really nice gifts, treated them like princesses, etc. But he refused to do any of that with you, he wanted to be frugal with you even though he has more than enough money to treat you. Wouldn't you feel a little bit weird about it? Wouldn't you question why you were different, why he didn't care to treat you the same? Why the sudden change?