
Hi, Ace/aro person here with an Ace/aro partner: asexuality and aromanticism are lack of sexual and romantic ATTRACTION, so you could still be dating/having sex while ace/aro. The attraction is the initial pull, not necessarily the act of sex itself. That being said, if your friend defined their RELATIONSHIP itself as ace/aro, they may have what is often called a queerplatonic relationship (QPR)
This is what my partner and I have. Everyone defines it differently, but generally the idea is: This is not romance, but we are committed to each other and connected in a way that’s different from friendship. My partner and I live together, we want to get married someday, we want to spend the rest of our lives together. We’re friends, sure, but we’re also life partners. We just don’t have sex and we sleep in separate rooms.
Again, everyone defines it differently. QPR is an umbrella term. But going back to your specific situation: I’d say if your friend says it’s not just a friendship, it’s not just a friendship. Sometimes relationships are hard to define. It’s okay if you don’t get it, I’m sure what really matters to them is that you respect that their relationship is important to them, even if it looks different than most people’s. That’s how I feel when I tell people about my QPR, anyway.