It hurts to read your last sentence because I've been thinking this. My fear is that I will call things off with my fiance and I will never find a woman that's as good as her. It hurts a lot but I like to play it safe so I think that unless something changes soon, I'll just have to settle with her.
I think you may have just answered your own question here...
Never settle for somebody.
It's obviously a big enough issue, pre-marriage, that you're coming here asking for advice. It's obviously important to you.
My advice - you need to talk with your fiancee about your sex life. Not what you want her to do, per se, but simply that it's important to you and that you have long-term concerns about your compatibility with each other.
You will learn volumes by how she handles a conversation of that sort.
So, if I read correctly, it's not that she won't do oral or anal, it's that she's relatively passive in bed, as well as not being outwardly sexual in general. It's not the amount of sex, nor even the quality of sex you're concerned about.
What it appears to be is that she shows no sexual desire for you, whereas this other woman, apparently, would. It also seems as though, according to you, it's a cultural thing, in that women are likely taught to be somewhat submissive, perhaps? As in, don't turn your husband down, but wait for him to come to you, etc.
To be blunt, that kind of attitude is no fun (trust me...). What you want is to be desired, and to not be the only one who shows any interest in sex. Never turning you down, and otherwise doing everything in bed that you ask (minus oral and anal) is not what you want.
You see this other woman who is not like that, and it's understandable. And now you're questioning the whole thing.
But again, you used the word "settle", so you've answered your own question, IMO.