Jane and I met when I was a student. Once the relationship had caught fire, and we started living together (she was working and had a flat) she supported me financially if needed. I hated it but I knew Id be earning one day. It wasnt untill say three years of employment that my earnings equalled hers, then overtook her. Then the kids came along, and even though shes had a couple of part time jobs since, the roles are well and truly reversed now. She is constantly aware of how little she puts into the relationship financially, and I have a hard job convincing her that I'm more than happy as we are. I do think its psychologically worse for the male in this type of situation, but its the relationship that counts, not the relative earnings. If your lass is happy with the circumstances, whats the problem other than your possible feelings of inadequacy ? If thats the only problem, and she convinces you you have nothing to worry about and your relationship will remain strong whatever the financial situation, then you should work with that. Accept things as they are as good, and move forward. Things are bound to change, and if they dont you still have each other.
That said, if you think the relationship has no long term basis, stop 'borrowing' money from her now, and start charging her for sex.