I know that feeling very well. It knocks your confidence massively…how can you ever trust someone again?
I left my version of this 12 years ago, my dc are largely grown up now and I do trust my judgement now, largely because of what happened.
I really do have an excellent radar for spotting these types now, I can do it in minutes. At work, I am known for being able to do this. Friends always check in on new relationships with me, And I’ve not been wrong for a long time on it. It’s hard to explain how I’ve got to this point, it’s many many things.
The first thing that’s important here is what pp have mentioned and what I call ‘the innocence complex’. A lot of us who were duped live in a bit of a ‘everyone is lovely, everyone has potential, see the good in everyone’ type of state and that just isn’t healthy, realistic or helpful. There is a balance to be struck where you are not totally cynical about everyone but you are also aware people can be cruel, nasty and unkind and they may not have potential or want to change, they just are malevolent.
They do give away signs, they are there. You just firstly have to be prepared to see them, as above, but secondly have the confidence in yourself to acknowledge those signs when you do see them. By that I mean, it’s actually really hard to stand up and say “there’s something about that person that I don’t trust”. Usually these people are 95% charming on first impressions, so most people will conform to our natural human state and ‘want to believe they are good’ so will go along with them. But if you’ve seen the 5% leak out, it’s sparked your senses, are you always prepared to say something / do something? It’s very hard to because it’s you who looks like a cynical miserable twat not them.
There have been many occasions in my life where I’ve spoken up about people because I’ve seen a 5% leak behaviour and others have thought I’m completely revolting for saying such things. Unfortunately, time always proves me right and I’ve lost track of the number of times people have come back afterwards and said “you said it years ago”. I find it fascinating now that people always remember my comments years later. I think it must hit them somewhere, they must also know that there is ‘something’
Anyway, long post. But I just wanted to say, you are very right not to trust your judgement at the moment, especially if you can’t work out what signs you missed because I know there will be signs. Do some reading on personality disorders, get to know the patterns of behaviours in cluster b personalities, the dark triads. If you can start to look back and see signs, they may not even by 5% signs more like 1%, then you will be making a start on protecting yourself in the future.