are we as "men" expected to do all the heavy lifting (not literally) for women and that's just something that we have to live with our entire lives?

NO!!! Your gf is toxic af, manipulating you, and using you. Setting aside the fact that the homework is her responsibility, that it’s cheating if someone else does it, and the point of homework is for her to LEARN the material not that it just gets done, her ignoring your needs and saying hers matter more, is just crazy. Where dies it end? If there are guys to do all her homework and they’re happy yo do it cuz she’s pretty and says she loves them and cries, let those men have her. Because that gets old fast. Find you a partner that helps you as much as you help her, and you’ll be way better off. And just fyi, crying can mean someone cares, but if all they do is cry and don’t back that up with action, ie also DOING things to show they care like taking your needs into consideration as much as theirs, then it’s just manipulation. Break up with her, let her do her own damn homework and find a better girlfriend cuz your current ones suuuuuuccksss!