Cheating girlfriend?

So i was gonna google something on my boyfriends phone of 10 years because my phone was dead and i saw that he was looking at porn..Whatever..i don’t like it but he is going to do it anyways. This time i saw one of the porn “categories” he was searching up was “cheating girlfriend” ? Like a bunch of videos captioned” girl riding d”ck while FaceTiming her boyfriend” “Girl getting f*cked while boyfriend is out” just random things that fall under those categories and lately he’s been working a lot and i know he’s been working cause he FaceTimes me and i calculate his hours for him and his hours match up what he gets paid...but we also haven’t been having sex like we use to since he started working cause he’s always tired! Why would he search that type of porn specifically? Any opinions?