Bf called me his ex wife’s name..

Ladies I need help. My boyfriend talks in his sleep but I never really carry on a convo. Well he asked if I would record because he wanted to hear what he says and all. So this time I carried on a convo when I realized he was sleep talking. I turned over and he started laughing so I thought he was awake and said what’s funny he said he was trying to figure out the dials on my phone. So I knew he was sleep but this time completing sentences which he never does.. I started talking to him and he would reply and then I asked what’s my middle name and his reply was breann. And I got silent and he said oh wait no it’s ____. Idk where breann came from. Breann is his ex wife’s middle name. I’m not sure if it’s because im pregnant but it literally hurt my feelings to pieces. Like he says it instantly so was she on your mind. It took him a min to realize he said the wrong name... Am I overreacting or would y’all be mad too?? Like to me it’s like ok you’re laying beside me, your pregnant gf, but you’re thinking, imagining, or wishing you’re beside her.