Anything can be a trigger. Even things that aren't sexual, if they often led to looking at porn. An example I often use is the beer after work. If you sat down with your computer with your beer and looked at porn, that beer will make you want to look at porn all the more, and switching away while trying to quit can help. Ultimately you'll have to be the one to answer those questions, but they are good questions to ask regardless.
New video game characters are definitely very sexual at times, especially in Street Fighter. This can be a problem, especially if someone's personal porn preference leans towards the CGI, animated, or otherwise exaggerated type. It is the norm for porn tastes to evolve (devolve?) into something pretty far off the beaten path, so if that applies to you, I'd say it is something to take to heart.
Maybe you can switch to classic Street Fighter II... pretty tame, and just don't use Chun Li!