The condoms always break...?

I just lost my virginity to my boyfriend and I really enjoy having sex with him, but every time we have sex the condoms we use break, we've tried every brand and even gone up a size and they still break. It makes him very VERY nervous when they break because of pre-cum and we are still working on our futures. We've stopped and hadn't had sec for 4 months and then today we did and it broke(before he finished) and now he's freaking out and I want to fix this so we can be okay layer down the road. How do we get them to stop breaking?