I also believe the law should stay as it is. Men can become fathers accidentally, and indeed through subterfuge, is it right that every time a man has sex he takes a gamble with half his net worth?
But that's two extreme options. It doesn't need to be equal rights for cohabitants, and nor does it need to be that the mere fact of a shared child should qualify a couple as having reciprocal obligations. It should, IMO, be a qualifying time of cohabitation, with the time longer for those without children, and it should be less financially protected than marriage. But it should not be the case that a long term relationship with children has no legal status at all, if a split leaves one party in dire financial straits.
I know a married woman with 3 children, terribly unhappy, but claims she can't leave because they wouldn't have the same standard of living and type of house after a divorce. He has a good salary and the house is probably worth around £700k with plenty of equity. So it seems that the 'security' of alimony doesn't provide some women with the confidence to start a new life either.
There is a marked difference between choosing to remain in an unsatisfactory relationship because the lifestyle makes it worth it to you, and being potentially forced to remain in an abusive one because the alternative is homelessness. It also assumes that the decision to end the relationship is always on the poorer party. It isn't. An unmarried woman can be forced out of the family home, with no claim on it or savings, if she has not paid towards it - even if lower wages paid for food, or other family expenses. That can be so after decades, where she has performed all the labour of maintaining it and caring for the children. A married woman is assumed to own an equal share.
That's even without the issue of who is the legally entitled party if one side is ill, or dies. Let alone where there's no will - which happens painfully frequently. And sure, that's careless. Not sorting things with a solicitor may be, too. But people are careless, and should the penalties for that really be so desperately high, and payable just when their lives are, by definition, already in pretty awful places? When bereaved, or facing relationship breakdown?