take a plan B?

Gabby
My partner and I have had sex without a condom about 3-5 times before and even though he pulls out I still feel the urge to buy a plan B. He always reassures me that he did not cum inside of me and he rarely pre-cums. Though, I am sure he pulled out before he came should I buy a plan b? 
Ps: I've already taken 3 in the past month so I truly don't want to buy anymore ..... (yes, I know I should find a better way of birth control...)