First of all - the woman should receive enough money from the man so that her standard of living doesn't go down at least for a while
You and I both know that it doesn't always work like this in reality. There are lots of men who leave and do not provide.
So, if the man leaves the mother with a child and doesn't provide, what should the single mother do to improve her financial situation, given that it was previously a reasonable situation before the relationship broke up?
I think everyone should be forced to enter into a pre-maritial agreement with lawyers provided by the state if necessary so these problems can be argued and decided before marriage and then that should be binding.
Sounds like the only winners in this scenario are the solicitors.
Bearing in mind that legal aid has been cut drastically over the last 5 years and access to justice is at an all time low, do you really think it's practical for the government to pay contract lawyers to negotiate prenuptial agreements every time a couple get married? It would cost crazy amounts of money.
You would no doubt then complain that people shouldn't be getting married on a whim because it costs the tax payers money to pay the lawyers.
Prenups aren't worth the paper they're written on anyway. If you think about the situation you're trying to solve (woman being left to bring up a child and not having enough money), do you really think she will have the funds to bring a breach of contract claim through the courts? Or do you think that should be funded by the state as well?