this "just habituating with someone for 10 years is enough for the courts to consider you effectively married" is completely false and a myth. Especially in California.

Only a few states have something like the common-law 'marriage' you picture - but it's a really high bar.

There needs to consideration AND usually clear intent to marry (w/ nuance of course);

You can't simply fall into this by happenstance because you cohabitate for {n} amount of years.

California does have a (ever barrowing) Marvin Action.

But it's an incredibly high bar and not family court

You need to prove that essentially a contract exists between the parties; * e.g. consideration *

https://www.wgslawfirm.com/family-law/divorce-mediation/2025...