I married my military ex before even living together let alone having dc and he knew/I told him that was my stance. NOT because I am a traditionalist but because even at 21 I had seen the consequences of not being married before entangling finances/children.
My friends dad died very unexpectedly when they were very young. Not being married she got nothing, lost the house (his parents inherited and didn't care she and his kids were left homeless), no pension, no life insurance etc. she had mistakenly thought 'common law' was actual law.
A relatives partner was in a terrible car accident leaving him in a vegetative state. Again 'ils' screwed her and kids despite them being together 15 years and 2 dc. They also ignored his wishes to be a donor following having his life support terminated (also against his beliefs).
Mums friend living with a guy 20 years following his split from first wife (NOT ow). Because they weren't married it was easier for his kids from the first marriage to challenge his will and get the house leaving her homeless. House was in his name even though she paid half the mortgage. Again mistakenly thought 'common law' applied. She also thought she'd get some of his pension.
Sahd friend of mine, came downstairs with their toddler son one morning to note 'sorry I can't cope'. Couldn't get hold of her. House in her name as she was the earner. Lost house, nightmare getting maintenance (almost 7 years) as she went down the Se route but also because Csa and benefits people demanded ridiculous amounts of proof that he'd been sahd (that they wouldn't have from a sahm. Sexism works both ways). She then decided after 10 years she wants full residency (whole other thread I know).
I tell people irl and on here to protect themselves financially IMO that inc no joint accounts or debts!
As for those 'well dp would never do that to me/the kids'
Are you really so arrogant as to think affairs/disability/death only happen to bad people?
I can assure you nobody I know that's been through a relationship breakdown ever thought the person they fell in love with could do half the things they do end up doing!
My ex was raised by a single mum and when we were happy he'd actually tell off friends of his that bitched about paying maintenance etc first thing he did when we split? Emptied the joint bank account!! I had a 2 yr old and no income!