porn...please help!!!

So my boyfriend of 3 years and I have been  having issues with porn. I only see him on weekends and we have a good sex life, it's just that recently he's been masturbating to porn every day. We had sex like 4 times this past weekend, but on Sunday through today hes masturbated. I've tried to come to terms about it but can't. I'm so afraid that it's going to become so bad that I won't get any action or that I'm going to be second to porn, but he's reassured me that he won't be. I'm also confused because I've been talking to him about it this past weekend and he gets upset every time I bring it up. I told him I don't want him to be addicted to it and he said he was in his early teens. But tonight I was talking to him on the phone and tried to tell him how I'm scared and told him that if he's addicted to it, that's the line. Like that's where it'll become an even bigger issue. And he said "well I'm going to cross that line" and I asked him "so you're telling me that you're addicted?" And he hung up on me without a response and turned his phone off. I know I overthink all the time but I feel as if I can't even talk about it or voice my own opinions on it. I need time to understand and get used to this, and by doing that I need to have a conversation about it without getting into a fight. I just don't know what to do...I love him and he loves me.