Unmarried couples, how do you address your other half in public?

r/

So we are couple, 36M and 36F, in a relationship for over 4 years. We are not married and we are not planning to at the moment.
There’s something I have been ‘struggling with’ lately and it’s the way I address to him when I talk to other people. I tend to use the word boyfriend because yes, we are boyfriend and girlfriend. But the label ‘boyfriend’ feels as if we were a couple of 17 year olds!! I don’t know if you get what I mean, we are two grown-ups in a solid relationship!
Recently, I’ve been trying to use the label ‘partner’ but it feels off. He addresses me as
‘his girlfriend’ and I’ve jokingly said to him exactly what l mentioned above. So my question is: for unmarried couples, how do you address your other half to others? What labels do you use?

TL;DR
What labels do you use in front of others when you’re in a solid unmarried relationship in your 30s?