My [26f] boyfriend [27m] has waifus. How do I (not) bring it up?

I've been with my boyfriend for almost 8 years now. We started living together a bit over a year ago.<br><br>When we were first dating, he told me about how he used to play a lot of video games, and how he used to have anime waifus. He even told me that there was this one character in a visual novel he played that he was "in love" with, and how he (effectively) courted her, got to the "good endings" (whatever that means), and all that, and how he felt "driven" to do that. Apparently, the term for this is "waifu."<br><br>Not a big deal in the grand scheme of things, or so I figured.<br><br>Anyway, I was using his laptop to check my email real quick (he was out of town for a couple days), and I noticed in the address bar some autocomplete stuff. It was stuff like "so and so with a ponytail" and other specific search queries.<br><br>Curiosity got the better of me and I opened up the browser history. There were a bunch of sites relating to waifus and stuff, but one odd thing (besides the fact there was so much of it) was that the sites were all on the "new" domain (like .tube instead of the real one, which is .com). It was all recent, too, from the past few days, when he was away.<br><br>Apparently, he has a bunch of subscriptions to some NSFW stuff.<br><br>Crazy part is: he's paying for all this shit.<br><br>I checked the credit card bill, and there were plenty of charges to various NSFW-related businesses. The odd part is the credit card he used has a really low limit, and he always makes a point to pay off the balance when it comes in the mail. He always pays for everything with it: grocery shopping, buying gas, restaurants, whatever. Even the credit card company called me to check if it was really him making such charges, and to confirm I was with him when he made the purchases.<br><br>I get it's mostly for the porno, but I still find it annoying as all hell. I have better things to do than field calls from my credit card company.<br><br>I confronted him (not directly about the porno, just that his browser history showed a lot of recent activity) and all he said was "I was just proving something to myself" and "I was just curious", but wouldn't elaborate on any of it. He did say he'd "stop" whatever it was he was doing, but he seemed angry about it.<br><br>I don't know how to (not) bring it up. He clearly doesn't want to talk about it, and my gut is telling me to let it die, but I feel a bit weirded out by the whole thing.<br><br>What should I do here?