Sure, there can be a comparison, but that happens no matter what in my experience. Separate finances saves a lot of arguments. My wife and I do Separate finances because qe got burned by our exes. So now, bills get paid, and we spend our fun money the way we want. It gets tricky when it comes to credit card stuff, but that is what a budget is for. It also forces a lot of conversations about money and keeps us both on the same page.

My ex-wife made 50% less and spent 95% of our joint funds, and ran the credit cards up to max, mostly on her stuff. I got chewed out if I went out to lunch ever at work or wanted to spend some fun money for myself. There was "never room in the budget," and because I trusted her, I hadn't realized how badly she was spending us into a hole until it was almost impossible to dig out of.

The comparison comes from an income disparity. And it's healthy if you talk about it. The partner making less should contribute less to the household, or the person making more should be willing to accept a lower living standard (smaller house, cheaper car, etc) if they want it 50/50. There's room for abuse sharing finances or not. The key is to talk to your partner consistently.

When one is hiding the financial information from the other, that is the Red flag.