Condoms keep breaking...?

My now boyfriend and I have had sex 3 times. First time was unprotected and I needed to take Plan B. Second time the condom broke and I needed to take Plan B. Third time the condom broke AGAIN and I needed to take Plan B AGAIN. I know how terrible it is for my body, and I'm planning on never having to take it again . I'm going to start on birth control soon, I just need to wait till my period starts (if it starts). But what I don't understand is how the condoms KEEP BREAKING. I see him put them on and he does it fine, even i've put them on for him and it's fine. But 2 times means there's something wrong with me or him. Does anyone have any suggestions? They were completely different brands and packs and they were brand new, straight out of the packet. I've been with other guys before and they haven't broken. Thanks.