GF and mom problems.. need help?

ok, so i've been with my girl for 5 years and seriously considering to tie the knot with her. Anyway, been getting flak from my mom and I hate it how she indirectly and underhandedly keeps bashing her when the 2 of us (mom and me) are together or when I go visit. It's not the she is not good for you, but more of the "why do you always have to drive for her" "why do you always have to pay" "why do you always have to wake up" ... and the "why can't she" ... I can take that kind of abuse but it lately, for 2 months, itjust hurt like a knife because I overheard her talking to my aunt about her friend's son, who is about as old as I am and also has a long-time girlfriend. Says things like, "Jay is such a sweet kid.. brings his girlfriend to school and picks her up.. such a gentleman and always offers to do things for her" "Such a lovely couple" "You rarely find that kind of guy today"... and yes, nothing about me. But that doesn't affect me. what affects me is the fact that I am freakin the same or better and I dont see why I am seen as wrong/a sucker/doormat/etc when I am not. Heck, my girl isn't even high-maintenance and she is happy with our current lifestyle. Any advice?