Anyway the point is you need to trust him. He isn't bisexual or bicurious, he just loves to get a reaction out of people -same with his friend.
He also has pictures of kissing his friend (male) while out at a pub. which don't look it up- but it's quite homoerotic. My husband likes to send his friend a gif image called meat spin. That being said some guys also just get amusement out of such things. There are also pop up ads, although you did mention phone so it's much less likely it was an accident. Also many porn sites show different pictures from separate porn types without being sought out. It's possible he's bisexual or bi curious. If your boyfriend isn't open about his sexuality then he is probably very sensitive about it and needs a little time to open up about it. yes- But that doesn't mean that your relationship is in jeopardy because of it. Pregnant porn, MILF porn, masturbation, anime, etc. I don't know of any straight men who are into shemale porn.