You really should break up.

If it was flipped and he were to make a lot more money than you, would this make you try harder to match him or would that be fine with you? Most women want a men who is more successful then themselves and earns more money. It is totally natural. However don't say its about both providing half....

You tell him that he should not propose because you do not want to get married to him and if you are honest you should actually break up and give him the chance to find a partner that is more suited to what he wishes for.