One thing that drives me potty on these threads is people making out that if you're married, you get a say in medical treatment more than if you're not.
People often saying "I got married because I didn't want my partner's mother making the decision to turn off the life support" are wrong.
Without a LPA (which you can get for a friend or relative, nothing to do with marriage), no one no one can consent or decline treatment for another adult. Family members (including partners) would be consulted in a 'best interests' decision, but no one other than the medical team would make the decision about life support etc.
The exception is the mental health act. There, there is a category of "nearest relative" who do have rights over sectioning (and therefore treatment) etc, but only for a mental disorder (so still not ever turning off the life support). But, guess what! As long as you and your partner have been living together as a couple long enough, you're the nearest relative, whether married or not!
So, in health, in the UK, long term partner is the same as married, and staff should treat you no differently. Even if you are married, you cannot consent or decline treatment on their behalf, you cannot ask the life support machine to be switched off, and staff should not tell you anything without checking with the patient first.
There are benefits to being married if you're the lower earning partner.
There are benefits to not being married if you are the higher earning partner.
No one is being 'irresponsible' by not being married these days. Marriage (and subsequent divorce) can be a complete disaster for a modern woman.