Fictional characters are scientifically designed to evoke strong feelings such as you are experiencing. Take Samas's Zero Suit or just the tradition of getting to see her in skimpy outfits if you finish the game quickly; the effect this has on you is pretty much 100% guaranteed to work like a drug. You will be affected, you don't really have a choice of controlling that except to partake or not, or, if you do partake, then you choose whether you escalate how you partake.

Or to put it another way, the stuff built into those characters and how those characters are portrayed officially, is like beer at the bar, and the internet's Rule 34 material is the hard stuff you drink alone, ha ha?

Another perspective is that there is no real right answer as to how much lust or deviance is okay, normal, and healthy, vs what is too much or too little; it depends on you. That said, there has been a lot of talk in recent years debating whether unnatural sexual stimulus such as cybersex, porn and hentai, is just plain bad for our sex lives.

In short, I don't know whether you want help with killing the guilt or with killing the craving. You seem at least somewhat repressed about lust, perhaps extremely repressed, which I say because I can relate. It's arguably a lot more normal and healthy to have sexual feelings, active fantasies, even desires or plans for actual sex with actual people you know or don't even know, than some of us were raised to think.