Do you get jealous in your relationship?

My boyfriend and I have a really good relationship. I trust him and he trusts me which is great. But we were talking about how this girl at our school will leave class just go give her boyfriend a blowjob, and how she’s so down for everything and cheats on her boyfriend and stuff. He said “she seems like such a fun girlfriend to have”, which started to make me think but I left it alone. The next day, we were with her at a wrestling tournament and I had to leave early in order to go to work. They were left there and talked, and when I got off and texted him he was like “yeah she’s so much nicer than you, she’s so easy to talk to.” The fact that he said all this about her made me so jealous and upset and he doesn’t even notice or think it’s wrong.