I watch porn every single day, but my computer is problem-free.
Although, if I get a virus due to watching porn, then it's worth it.
Happens to the best of us. For the future my advice is MSE, lightweight, doesn't mess with games, very un-intrusive, very simple to use and works better than most of the freeware AV programs.
While people like you generally run without AV for long periods of time or feel that they are adequate enough without it, here's a little tickling piece of information you might want to consider:
Virus infections including those labeled under malware, trojans, viral infections, and others are created daily. They outnumber the possible virus definition updates by five-fold on any given day. What this means is there are so many created and dispersed so often and so quickly, it's best to have at least some form of AV installed to aid in prevention of infection.