OP, as others and I have said, this is all in your power to change. It won't change the past (and plenty of us - too many sadly - have had similar experiences) but you can change how you feel about the present and the future.
I'm obviously aware of how different my life could have been.
I see the way my partner looks at his adult children with utter pride and love and I'm reminded that I never had that and never will.
I see my colleagues progress into management roles - some of them 20 years younger than me - and I'm aware that that will never be me and, even if I started now, I'd never achieve what they will.
I see plenty of friends, peers, colleagues who have such more than me. Not just materially but in terms of the family love and support you talk about. But I also see the sadness. The infertility, the loss, the stress, the failed businesses, the less than perfect (by a long shot) marriages that they hide so well.
I see people with long term healthy friendships and relationships. I don't have those experiences because so much of life was spent in survival mode.
But I don't compare them to myself. It's not about being happy for other people's good fortune, it's about recognising your own too.
You have a partner who loves you and wants to live with you. You have children when many don't. You are alive. You're not on street drugs to numb the pain. You are, presumably, young enough (I don't recall whether you've given your age) to make huge changes to your life.
One thing my brother said to me when we were in our early 30s and were really just starting to fully understand the impact of our upbringing (rather than just survive it) was that we couldn't change the past but we could change the future. We could be the parents for our children that we never had. We could create the family for our children that we never had. We could make sure we broke the cycle. And that's what we did.
My children amaze me. I see their confidence and their opportunities. Their self assuredness and the feedback they and I receive about them and that is my legacy.
Not a nice house. Not a long marriage. Not a healthy bank balance. Not climbing to the top of my profession. Not nice holidays. Not a new car. Not anyone feeling proud of me. None of the extrinsic rewards you are looking for or the successes you (and I) see in others. But knowing that they will never feel the way I feel about myself. Knowing they know they are loved.