My boyfriend called me his ex girlfriends name...?

so last night when i was laying down with him and we were playing around he goes "er, stop!" we were play fighting. I turned around and said "what were you just about to call me?" i said " all i said was arrr" so i got mad turned around and he tries talking to me...telling me are you serious right now we were just playing around and all i said was arr...i ignored him for bout 5 mins then he turns around and says fine you wanna play the silent treatment we can both do this....about 10 mins after that i asked him to face me...he did, i said what's my name? and he said my name and then i asked "so what were you bout to call me?" and he said "erica". i turned around, turned off the tv and cried. This is not the first time he calls me someone elses name. It's actually the 2nd time and one time he introduced me as katherine and didn't even realize it. But this is the first time he calls me his ex girlfriends name and knowing abou how their relationship was and constantly hearing a story bout her doesnt help my thoughts into the whole thing. He said sorry and he tried to put me in his arms and make me fall as sleep but i didn't even want to be near him. They had been together for 3 yrs and broke up cuz supposably she cheated but he doesnt even know that for sure. I'm constantly hearing a story bout her and honestly im also constantly being compared to her......so what do i do?