I can't stop thinking about how my parents treated me

Hey, sorry if this is posted in the wrong area, I haven't used this site in years!
Anyway, onto my question. Growing up for me was horrible both my parents were abusive, my dad used to beat me physically resulting in me breaking my nose twice and my mum was emotional, telling me I should and I quote "go jump in front of a bus" or "play with the traffic" kill myself, I'm useless etc. It was horrible I was depressed and extremely suicidal, a few years ago I met my current girlfriend and I viewed it as a opportunity to finally leave home, even though we had been together a few weeks, I decided to leave (wanted to for my whole teenage years) the day I left my dad pulled a knife to me and said if I leave this house he will kill me, thankfully the police came and I left and I've never slept there again, see now his is the problem, I get on with my parents now, they're overly nice. Buying me things, giving me money and stuff, it just makes me think why wasn't they like this years ago.. anyway my question is I just can't stop thinking about the past and how they treated me I recently started going to visit them quite a lot and got them to drop me off around the corner they then started moaning asking why I don't want them to know where I live and since then I've started thinking about how they treated me, and how I feel guilty when they should I have no idea what to do.

You should not feel guilty, you have very good reason not to let them know where you live. Why they are so nice to you is a good question. Could be a number of things some of which might not be good, or they could have had a change of heart after you left. People do change. Maybe family counseling might be a good thing or sitting down and talking to your parents about it? That could go either good or bad. Or you could just leave it and work through it yourself, maybe seek professional help on your own and enjoy your parents change. Just some suggestions, you need to use what will work best for you, what will give you peace of mind and keep you safe.

Three things matter:

Are you happy, healthy, and safe?

Unfortunately with your parents you were not. Logically you are better off, but emotionally, I understand why you feel the way you do. I would be cautious with them still, and not move back in until their true colors show again. It will be back in time.

I think Sci-Fi's advice is very good and logical. I would definetely seek out a trained professional's help and advice on a situation that grew at the time as dire as you mentioned before taking a first step. I'm a cautious and borderline paranoia person to start with, I probably would NEVER even have approached them again, especially after having a knife to my throat, but I can't relate to the situation in the same way since my relationship with my parents is far from being the same and I know how important they can be to one's psychological well-being.
So speak to someone about it, don't go into this alone, is most of the advice I can share and I hope everything works out for you.

Your parents still did that they did, you are justified in your feelings, whether they are confusion, resentment, sadness, etc... Anything they do today will not erase what they did yesterday. It is up to you to decide how that will affect you going forward. I think once you've come to accept it (as much as you can, anyways), and accept that you know two different versions of your parents, it will hopefully become more easy or at least bearable for you.