Yeah I'd divorce her. But not because she slept around, that's actually not an issue. The issue is the fact that she omitted that shit to the guy she's going to spend the rest of her life with.
What kind of man does she want for a husband? A virgin? One on his deen? A stable man with no past?
If so, then you have to look yourself in the mirror and ask yourself this question: do I deserve to be with this man? Compared to me, would he consider a woman who did what he did instead of me? Stayed a virgin, kept her deen and lived a stable life?
It's all about lifestyles. Live the one that makes sense for you and choose someone with a similar lifestyle.
I ain't the most religious man in the planet, and I intend on being in relationships before I get married because I'm focused on my career, not starting a family. Because of this, I don't expect myself to be with a nun. I'm not the kind of man who should get one.
If you're talking about a reformed woman, then she should be with a reformed man.
The lifestyle that connects you and your potential spouse is what should dictate your decision making process.
And besides, a man on his deen will have expectations at home. So if you're not a woman on your deen, you'll get frustrated.
So if you're a young woman, who didn't do anything yet, ask yourself this question: what do I want out of life 10 years from now? If an action you perform will take that vision away, don't do it. Live like this.