how to make your gf contribute

hi all wanna know how to make your partner contribute to the living expenses. she's making good money but refuses to chip in on rent nor living expenses. we have been together quite long but cannot get married as our jobs are not stable. I feel overwhelmed by the expenses and the fact that I am also repaying a lot of debt at this time. Any recommendations on how to discuss finances with your partner and make her contribute? We end up having an argument whenever I bring up the subject!