I have sympathy for both of them.
The poster for being in a situation where she is not "mistress in her own home" and the mother-in-law for being spurned as too helpful.
But I don't think what is needed is sympathy alone. I am sure the poster gets plenty of that from her young friends, and the MiL from her older ones - though it sounds as though she does not have very many of them. Sensible advice and suggestions are what are needed.
It is the two-women-in-a-kitchen scenario, and will not be completely resolved until there are two kitchens.
Sorry, but I can't help looking back to my own student days. A baby then would have been a complete disaster. There were no creches, and I would have had to stop studying and be a housewife. My boyfriend would have had to leave too and start being a wage-earner to keep us fed, and we would be in a grotty flat in a high-rise scheme, with both our familes thoroughly disappopinted in the wreck of our careers. So we made sure there were no babies. OK, accidents happen, and they do tend to join us at inconvenient times, but at least this one has a home and a father in work.
And in many countries, all daughters in law are expected to live with MiL on her terms and have all their decisions made for them.
You don't say where you live. The local authority have an obligation to house families, so you don't have to stay with inlaws, and you have the money to pay the rent without going on beneftits. Thousands of others have struck out into adult responsible life with less.
Persuade your partner that independent life now is better than sharing a kitchen until he can provide you with something better. Then you can work together to afford another home.