I'm worried about something my girlfriend said to me

I am not particularly making sacrifices in my current relationship.
My girlfriend pays about half the expenses, and while I am considerate, I am not the type to be overly submissive.
She herself is quite sensitive, but she is also responsible and not a bad person.
But somehow...
I have had relationships before, but I feel like I uniquely don't feel much affection from her.
Because of that, I feel myself becoming somewhat cold and detached. I haven't shown it outwardly yet, though.
Then today, she called me and said that in her past relationships, she used to fall so hard for her partners that she constantly wanted to see them and would even sacrifice her own life for them.
But now, she says she doesn't want to date like that anymore, and she can't bring herself to do that for me.
She said she likes that she can maintain a stable relationship while still protecting herself.
It's not that I'm looking for a passionate, burning romance either.
But after hearing this, I felt extremely unpleasant.
It might be because I'm sensitive, but my immediate thought was, "What on earth is she talking about?"
We started fighting immediately after she said it, but her conclusion was that she doesn't want to date like she used to, and that she likes me and likes our current relationship, so she doesn't understand why I'm upset.
For context, we are both at the age where marriage is being considered, and my social standing/specifications are relatively good.
Maybe that's why, but I can't stop thinking that she might have internally compromised by looking at my status..
I'm feeling increasingly terrible on my own, and I'm wondering if I'm just being too sensitive.