I don’t get it. So you’re going to find out your current girlfriend had slept with 10 other men before meeting you. And then what? What is that going to change? If this somehow bothers you than it’s probably time to see a counselor. When I enter a relationship I do so with the person I know I can trust wholeheartedly. I trust that she will share with me things that she finds important for me to know. Just as I would with her. Everything else is noise.