Personally, my husband and I used this for 9 months and didn't get pregnant until we tried (happened first time). However, many people will tell you they got pregnant with it.
Months before I got pregnant (New Years actually) we got a little carried away and I thought I may have conceived then. I researched it A TON and found that the general consensus (and this is with actual medical studies--i can find links if you would like) is that pre-ejaculate (the clear fluid that leaks as a lubricant) does not contain sperm, unless the man has recently ejaculated and not peed since to "clean out the pipe".
If he truly pulled out in time, you're probably safe, but every method has a failure rate...he could have pulled out just a smidge too late...
but even then, it can take the most fertile of trying couples months to conceive, so i'm guessing odds aren't in your favor.
good luck though! When are you guys planning to actually try?
side note to readers: it is my personal opinion that you should never use this method unless you are prepared to have a kid in case it fails. the OP is obviously OK with another kid, so i don't think lecturing her on not using this as a reliable birth control method is helpful