I have to bear all the expenses of my girlfriend. She spends a lot. What if I can't afford her?

Just tell him you can't afford it, or you will divorce even if you get married in the future. Just tell him he can scrimp and save, or you'll have to change people. You still need to find a woman who is down-to-earth and will live within her means according to economic conditions. Of course, if you marry such a woman, it is also your responsibility to try to make her live a good life. Finally, I wish you happiness.