Adult content in a relationship

I know this might sound silly to some, but I really need some advice. My boyfriend (21M) and I (21M) have been together for three years. We didn’t have sex for the first two years, and even now, our intimacy is quite sporadic. To clarify, he is definitely not ace. Recently, I found out that he’s been subscribing to OnlyFans, looking up girls on Instagram and TikTok, and following or liking their posts, though he hasn’t made any overt moves on anyone. When I confronted him about the OnlyFans subscriptions, it hurt my feelings. I’m open to sex and willing to explore new things, but I don't see myself as conventionally attractive; I’m a bigger girl, which can be more of an acquired taste for some. The girls he’s been following are entirely different from me—they're either skinny gamer girls or fitness enthusiasts. Since discovering this about six months ago, I’ve tried to lose some weight and have lost about 20 pounds. When I first brought it up, he promised to stop and acknowledged that it contributed to our intimacy issues. However, four months later, I found out he hasn't stopped. He admits it feels like an addiction, expresses guilt, and insists that this time will be different. I discovered this again about a month ago after asking him directly; I’m not sure if he was being truthful about whether he continued until just before I asked or if he was nervous about getting caught. He’s begging me for another chance, and I’m willing to give it to him, but our intimacy hasn’t improved much after that initial promise, which raises concerns that he may have slipped back into his old habits. Should I bring it up again or try to trust him? I can’t shake the feeling that he’s looking at other girls or watching porn, which has left me feeling insecure. I didn’t feel unattractive until I discovered this six months ago, and it’s been weighing on me. How can I learn to trust him again? Any advice would be greatly appreciated!