Bringing up his ex?

So i'm on my period, and maybe i'm just a little emotional, but i honestly don't know what to do. I just now decided to bring up the fact that he always brings his ex up (well it's been maybe 2 or 3 times in the span of a couple months) but I still feel a way. He won't randomly bring her up but he'll bring up something she's done or said while we're having a convo. Any advice? I'm only 22 and this is my only real relationship i've had..lol would love some insight, maybe i'm overreacting? Is this normal? He was with his ex for a year and a half. They moved in together and broke up the beginning of this year i believe he said.