> I believe in the UK (where I live) one has all of the legal and financial implications automatically when a relationship reaches a certain age (3 years I believe). Legally you would be treated the same way as if you were married.

That's not true

https://www.moneyadviceservice.org.uk/en/articles/how-to-sor...

The sibling comment mentions family visas, and indeed those are not restricted to your married partner, but separation is completely different matter

There's a myth about such a thing as a "common law marriage" existing, but that's just that: a myth

https://theconversation.com/common-law-marriage-a-myth-neari...

Not an expert on the UK, but here in Canada common law marriage is absolutely a thing. Just filled in my 2021 census yesterday and one of the selectable marital status was "common law" and many government documents refer to the status. Common law relationships are generally much easier to dissolve, but courts have held them as strong as legal marriages, especially if the relationship lasts decades and includes children. They form without any specific action beyond time spent living together.

property on dissolving: https://www.ontario.ca/page/dividing-property-when-marriage-...

employment benefits must extend to common law partners: https://www.ontario.ca/document/your-guide-employment-standa...

Interesting reading, thanks for that. I have learned something. I was intentionally liberal with my use of the word "believe", because it seems difficult (to me) to prove the relationship without that piece of paper. I imagine (note I say imagine, this is based on no evidence or research),you could challenge it successfully in a court of law though, if required, for some reason?

The myth aside, I don't think you have "no" rights, the first link says "fewer". It's really hard to prove something without an "official" document though so I understand how it could be more complicated.

> the systems and conventions need to change?

I think that in many (most?) countries nowadays, marriage is already no more than just a legal status that offers those practical points, so I am not sure if anything needs to change.

You don't have to get a ceremony/ring/party, go at the church or whatever your culture/religion associates with the act of getting married.

You can just sign the contract privately, which makes you legally married.

Same for divorce, I believe it only gets complicated when you fight about children, money and assets, otherwise you can both just decide to stop the contract.

Also in the UK, plus one to everything above (with the caveat I have no experience in the children area)

For friends and family, the older relatives on both sides I believe just assume we're married.

There is one difference, and that is in default treatment. If I died/was rendered otherwise incapable of communicating my desires, there is now an onus on my partner to prove that we are in the relationship she claims we are. That exists with marriage too except it's "solved" by a marriage certificate.

Yes, the UK is somewhat special here.

They also apply the same treatment to foreigners coming to the UK.

So if you've been living with your boyfriend for long enough, the UK will extend him a spousal visa without you having to get married.