wtf just happened?

I'm 41 weeks pregnant. Baby will be here any day now. I have twice weekly appts to be monitored, and have one today at noon. Because my husband works during the day, I typically either go alone or my mom goes with me. She is planning on going with me today because we have errands to run in the area afterwards. This morning as my husband is getting ready for work, he decides he would like to miss work to come to my appt... He asks if my mom is coming, and I tell him yes. He asks me to cancel with her, as he'd like to be the only one at the appt. I tell him that Mom and I have errands to run, and that I'd like them both at the appt, and he starts acting all pissed off saying that he's not going to go. He wants it to just be him and I, and is making me choose between him or my mom. Finally, he storms out and says he'll just go to work, and that my mom and I can "have fun at the appointment" without him. I told him that I didn't like the position he was putting me in, and asked him why it was such a big deal that my mom was coming... he said, "it's not her baby. She annoys me so I just won't go if she's going". I'm so confused. I feel like my husband is being petty and putting me in a strange position. It would be one thing if the appointment wasn't in a few hours, but I feel weird changing my plans just to meet my husband's demands. Is he in the right here, or is he being petty/immature? He finally just left and said "you've made your choice, I'll get over it"