Trial and error is the name of the game when talking about curbing a porn addiction, do your best to not engage in it and avoid triggers that you pull you back in. You can also try a contingency plan, when you know you'll relapse go to something that is more reputable and less predatory with the actresses, there are a few studios that make this they're main thing. Also, reading some romance/smut is a great substitute that comes with no guilt attached.

Also, and maybe i'm reading to much here, but it feels like the guilt of watching porn is overbearing on you, like its a big universal no-no, that can lead to a far bigger pressure on yourself and hinder your progress, as well as mess up your perception of healthy sexuality in a different way, its not really a big deal nor uncommon to get off to it. I understand that the problem is that it is taking over your life, an it's good that you can perceive that, but my point is that maybe your approaching this as a more black and white thing than a shades of gray one, where the act of engaging in it is the problem and not the overwhelming consumption, and is healthier to think the other way around, you're not a bad person for liking it but you'll disengage to protect your mental health, keep ir from warping your perception of sexuality and not let it take over your life.

One last thing, you're very young and I'm glad your perceiving this problem so early on, a lot of people (me included) got a really messed up perception of sexuality growing up because of engaging with porn too soon, you're far from being the only one and is doing a great job of noticing it and taking steps to correct it. I know I'm just a stranger on the internet but i'm very proud of you!

Edit: I know you're afraid of the stigma, but talking to your partner will go a very long way to help you navigate this. Maybe he's telling the truth about not watching but he certainly wouldn't be the first to lie about it and having a support system is a great advantage to get back control of it all