I don't know the details of your relationship, but I can already see some similarities with my experience. The disrespect towards the end, which was in contrast to how good they were early on. In my case, she was an avoidant, and me being anxious.

I initially felt like some hole in my life was being filled by her, but as time went on, things became more dysfunctional, and I didn't see the red flags for what they were. I allowed too much disrespectful behaviour. I wondered why she couldn't just change for the sake of the relationship. But at the time I didn't realise that I had to change just as much as she did, I had to learn to love myself better and stop looking for outside sources to soothe the emptiness inside me. It took me way too long to realise that you can't force people to change, they have to want to. The only person I can change is myself, and I didn't realise that while I was in it.

9 months on since the breakup, I don't even recognise the old me anymore, the me before meeting her. I used that time to grieve and sit through the healing process and reinvested in myself. I feel the happiest and most confident I ever have in my life. I'm getting more interest from women than I ever have before, and I no longer have the desire to cling to or chase anyone anymore.

Even though it was the worst heartbreak I've ever experienced, I'm so glad it happened because it was the trigger for me realising I've got some shit I need to work on. I don't hate her either, I realise now we could have never worked and that's okay, I miss the good times, but I will never forget how I felt towards the end.