My condom broke during intercourse and 3 hours later my partner took a plan b pill. is there any advice you can give to ease my mind?

Pregnancy: Risk is very low when plan B is taking that soon after intercourse.

Yes: Plan B One-Step is up to 89 % effective when taken within 72 hours (3 days) after unprotected sex. It can reduce chance of pregnancy by up to 95% if used within 24 hours. It continues to reduce the risk of pregnancy up to 120 hours (5 days) after unprotected sex, but is less effective as time passes.

Most likely: It should work. Timing is good.

Preg. VERY unlikely: First, even if she did not take Plan B the odds of pregnancy are low; the average couple trying to conceive by having intercourse when fertile takes 6 months to conceive! Of course pregnancy is possible, but, as Dr. Fowler mentioned, taking Plan B within 24 hours reduces risk of pregnancy by 95%. So try not to worry too much, the odds are in your favor.