To think there are always missed red flags early on in eventual abusive relationships?

How many of these mystery women who admit to only finding out about the abusive true nature of their partner (particularly after children) have you actually come across personally ?
And what are these mystery red flags you believe they should all be spotting in the first throws of romance?
You do realise Narcissits and Sociopaths are very good at hiding behind the mask of sanity for years and years and that they target empaths looking for love.
How do you suggest we lock this down?

Sorry, this sounds like victim-blaming.

There are any number of reasons why women (and men) end up in abusive relationships and there are also many reasons why people don't just walk away.

Too many people simply declare, "I'd never get myself into that situation, I'd have walked away after x,y,z".

It's not always that straightforward. Don't judge anyone else until you've walked a mile in their shoes.

I think it would be more helpful to acknowledge that behaviour can be on a trajectory. So rather than being always present and overlooked (the missed red flag) or a completely new behaviour out of nowhere, that it's most commonly a gradual and subtle escalation. So we start from the basis that everyone has faults. And one of your partners faults is that he is a bit short tempered. But never with you and its over quickly. Balanced against that he is lovely in every other way. Then over time it gets worse, boiling frog style until one day you are living with a man who yells in your face and punches the wall. So, with hindsight being 20/20 we can match that to the red flag of his early flashes of temper. But in all honesty, few people assume minor faults to be portents of intolerable behaviour down the line. Otherwise, given there is no one without fault, then we'd have no relationship with anyone.

The first part of your post feels a bit victim-blamey. I suspect that yes, in many many abusive relationships there ARE red flags early on. But the problem is that the red flags aren't spotted because women have been socialised to accept surprisingly shitty behaviour. And to often, even when they DO flag up a potential issue, they're told they're "too fussy" or "too demanding" or "give him a chance" or "maybe he just...."

If I knew then what I know now, the very minor niggles I spotted early on in SIL's relationship would have generated MUCH bigger alarm bells AND I would have spotted a bunch of other red flags. But I didn't. and she certainly didn't. And PIL were in her ear already all the time about how "fussy" she was and how she "needed to settle down" and how she must "give him a chance."

I agree to an extent but it’s complex . Some people struggle to see the red flags because of their upbringing and their fixation with making it work, but I do think often they are there. Sometimes they’re genuinely missed but other times people close their eyes to them and just focus on their partners good points.

I had a co-worker whose mum is in a toxic marriage, her own Dad abandoned them and her stepdad who she also had kids with seemed awful. So perhaps that’s why she ignored the red flags in her husband who later became emotionally abusive, a cheat and aggressive . She had sang his praises the whole time I’d known her but when their 8 year marriage began to fall apart and I quizzed her on some things it came out at the very start of their relationship he had displayed some worrying signs like throwing a heavy boot at her in anger and he had also smacked their newborn when she was crying.

I think she was just so desperate for a family unit she shut her eyes to some things and hoped they would work out since his behaviour did improve afterwards. But the fact he had did those things in the first place showed his character really.

I think for many it’s easier to look back and realise what was going in their abusive relationship.

For me, the signs were there literally from day one. He love bombed me on our first date, it was very intense and I was uncomfortable with it. He went through my phone while I was asleep within a week of that and woke me up aggressively demanding who “all these men in my phone were” and calling me names. The person I am now would have dumped him on the spot But I didn’t trust my own judgment at the time. I was 18, he was nearly 30 so a huge power imbalance and I was easy to manipulate. I’d also grown up being emotionally and physically abused by my mother and had no other parent at home. My frame of reference on normal healthy relationships simply didn’t exist. The women (and many of their children sadly) I met in refuge had very similar upbringings and outcomes, lots much worse than mine. And yes, many repeated the cycle over and over often with worse and worse men.

Yabu. How could you possibly know that?

When you grow up surrounded by red flags, you think they are normal and don’t look too bad.

Its possible to teach others to watch out for red flags without pretending they must have missed one. If you've never been caught out its because of luck, not good management.