I'm afraid I don't have any advice either, but I'm in a very similar position.
I've been NC with my mother for over 2 years and every day that passes her impact lessens. I have friends; I have 2 wonderful children; an amicable relationship with my exH; a boyfriend who claims to love me very much...
But I'm not sure I really trust any of it.
I've also had counselling and it's really changed how I see myself, and how I feel about my mother, the strength of her ability to still affect me...
But I'm still not sure that I trust my judgements - is that person being nice because they like me, or because they want/need something from me; am I right to trust my boyfriend or are there red flags I can't see...
My mother also drilled it into me that I was lucky to get any one at all; that it was imperative I wasn't single because a single woman was just one who couldn't get a man and that was the greatest shame of all. As a result I didn't value myself enough to be single or find a decent man, and married someone who obviously had his own 'issues'; thus compounding the first 20+ emotionally abusive years of my life with my parents with a further 15+ years of an emotionally abusive relationship.
The bottom line is that I don't trust my judgement when it comes to other people either.
I suppose we just have to gather the evidence. If we trust someone and they don't let us down, well then we made the right choice.
I seek out completely different people to I did do before. When I spend time with my exH, I realise just how different he is to the other people in my life now, so I have to take that as a sign my judgement has improved... But I don't know it.
Sorry, that hasn't helped, but you're not alone. Not by a long shot. 