I am struggling with concerns regarding my girlfriend, dating, and marriage. Is there anyone who can listen?

At 35, I am considering breaking up alone as a "punishment" for meeting someone who is far too good for me.
Hello. I am an ordinary 35-year-old office worker. I have a 33-year-old girlfriend with whom I have had a beautiful relationship for two years.
She is truly precious and someone who is far more than I deserve. She cherishes and loves me so much that I wonder, "Will I ever meet such a wonderful person again in my entire life?" However, as I have recently faced the reality of marriage, I am seriously contemplating and wavering on whether it is right to continue this relationship due to my own inferiority complex and self-reproach.
The root of all my worries was the "gap in family background and environment."
My father collapsed from a cerebral hemorrhage when I was young and has been fighting his illness and recovering at home for a long time. Unlike my family, which lacked economic and emotional stability after my father worked his whole life following high school graduation, my girlfriend grew up in wealth within a good neighborhood and school district in Seoul. Unlike her, who has traveled freely to Europe and the US since she was a young professional, I don't even remember going on a proper overseas trip once. Her parents also possess excellent academic backgrounds and social status.
Whenever these differences suddenly catch my eye, I unconsciously fall into deep self-reproach and depression while comparing myself to her. Because I view myself as "lacking and miserable," I sometimes show a low sense of self-esteem in front of her or act defensively for no reason.
"Is it really right for me to keep seeing this person? No, is it right to let her go?"
One day, when these thoughts wouldn't leave my head, I finally blurted out that I needed about a week to think.
As soon as she heard my words, my girlfriend broke down in tears right then and there. Seeing her collapse, asking, "What on earth do you mean by that? Are you saying you want to break up?" made me snap out of it. Only then did I realize that my judgment was completely wrong, how madly I love this person, and how big of a mistake I had made. I immediately apologized, saying, "I thought wrongly, I said something harsh," and while things have calmed down slightly, she is still deeply wounded by the words I threw at her.
I desperately want to marry her. However, looking coldly at reality, my savings are woefully insufficient, and my family is in no position to provide financial support. Because I am the type of person who doesn't easily share my inner thoughts with others, I suppressed all these worries alone until they finally exploded, and I ended up showing the most miserable side of myself to the person I love most.
It is so, so difficult.
Is it right to continue this relationship on the premise of marriage? Or am I making this precious person unhappy because of my own greed? I would like to ask for the sincere advice of those who are more experienced in life and those who have already experienced marriage.