Partner meeting female friend

Hey ladies what is your opinion on this me and my partner have been together 1.5 years. He has a few female friends that he speaks to. Where we live everyone has slept with everyone. Except me as I only moved to the area.

So this female friend he has slept with but it was a long time ago like 8 year later ago and they have been friends for like 13 years.

He is going out to meet her for a catch up today just for an hour over a coffee

Am I wrong to be annoyed about this and a bit angry as to why he thinks this is appropriate.

I know it’s probs me just being a slightly jealous partner and feeling a bit self conscious and worried.