Pulling out

Me and my boyfriend have been having unprotected sex. He does the pull out method, which he has done with multiple girls before. He pulls out, and will cum, but the wants to start up again. I asked him about it, because I was concerned, and he said that with his previous girlfriend of a year and a half he did the same thing. I asked other friends about it, because I'm concerned about getting pregnant, and they told me to relax, and that there is nothing for me to worry about! Any advice?