He called me another girls name

I’ve been seeing my boyfriend going on 4 months now. He is sweet, brings me flowers, takes me on dates. Comes see me one or twice a week due to us living an hour away and him working everyday. Today he came over and 2 hours in we’re laughing having a good time and he calls me another girls name.

I got serious and asked who that was and he said his co worker , and then said it was nobody and to forget about it and not make it a big deal. I asked how is he expecting for me to not make a big deal out of him calling me another girls name.

I asked him to be men enough to be honest with me. He said it was his ex and he was sorry. I told him there’s a reason why you mentioned her name because he’s clearly thinking about her.

He kinda kept trying it to flip it on me of why I wasn’t letting it go and not making a big deal and I asked for space and I stayed in my room with the door closed and tears on my eyes , only a little which he saw.

He said your right and closed the door. He left and texted me sorry.

I really don’t want to be that idiot girl who stays around why being cheated or mistreated. But could he really just make a mistake and call me a different girls name ?

I was with my bd for 5 years and many times I’ve had to be very careful with saying his name because I know I can say it out of habit.

Any advice ? He left