Should I keep fighting for us?!?

So I’ve been dating my boyfriend for a year and almost four months and I love him so much and would do anything for him and he would do the same. Yesterday I saw some texts between him and a girl who was saying stuff about what she wanted to do to him and he kept asking who is this and stuff and trying to figure out who she was but she sent him a picture of her butt and stuff and saying she had a boyfriend. But then she asked him how long his thing was and he told her... other then that he was trying to figure out who she was. But I considered that cheating because he told her about himself and she was saying a lot of provocative things. And he didn’t stop her because he was just trying to figure out who she was. And I’m not sure what to do because it’s kind of messed up.