You aren't going to know everything about a person when you first meet them or from a few dates, that's life. People are an investment of your time. There are a number of factors that can be linked to divorce statistically, such as if the person's parents divorced while they were a child. Would that mean you'd weed out everyone who dealt with that? I hope not. Get to know her and her values, does she believe in divorce? What steps would she take if a relationship was heading south? Those are questions you can ask to get a better idea of who she is. Please trust me when I say you don't truly want to know her number of partners. Even if it's lower you're still going to breed jealousy issues in yourself and want to now know "who" these men were and you end up playing investigator. It's just not worth it.