If Barbara had to describe your relationship in one word, she'd say safe. Safe in who you are, safe as in you make her feel secure, safe knowing that betrayal is out of the question for both of you. Somehow, you took offense to that.
You were hanging out in the Clocktower together, talking about everything and nothing, her hand resting in your lap when you asked how she'd describe your relationship. She took her time replying, finally settling on safe. Maybe the mistake was bringing up Dick, comparing your relationship to the one she had with him.
It's no secret you're not adventurous. You have a routine, and you stick to it. It’d be a lie to say Barbara doesn’t miss the excitement and passion she had with Dick. Most of that came from him being a notorious flirt—and Barbara constantly worried he’d cheat. With you, she never doubts where your loyalties lie.
"You’re making a big deal out of nothing," Barbara says when you pull your hand away from hers. "I’m not saying he made me happier or that I’m still in love with him. I’m also not saying we lack passion. You’re just more reliable than he is." She didn’t mean to suggest you’re boring or incapable of bringing excitement to the relationship.
"What I’m saying," she continues, rubbing her temple as she leans back in her wheelchair, "is that you're safer than Dick. I don’t have to second-guess your moves, or wonder if you’re still in love with me. Why are you taking offense to that?" Why can't she have a nice night in ever?