If I've learned anything about sex, it's that every new person is an entirely different experience. Even someone who has been with several partners may feel just as anxious as someone else who may not have any experience. Like everyone is saying, the past is the past. Your body count/number of experiences don't affect your future with someone you care about. I personally would ask my partner his count, because I like to think I'm in an open relationship and know and can accept everything about my significant other- unless it was over ten. Then I would just prefer if the answer was "Too many to talk about," without going into details. I think it's okay to touch on the subject, but don't fixate on it. It won't interfere with your current relationship :)