no sense to the emotion

Ive come out of my first relationship a while ago,

Although with the logical part of my mind i know it was a bad relationship, she said how she would cheat on anyone to be with her ex which hurt me, she flirted with a lot of her ex's she was very very controlling and manipulative and made me deeply unhappy.

But despite all this even though she cheated on me at the end and was truly horrible in what she did to me in the last few weeks of the relationship i still find i miss her in ways. I think about the relationship a lot particularly as I'm stressed at the moment sitting my finals.

She said in the last conversation we had i was the best boy friend she ever had and then jumped straight into another relationship with in a week or 2 of dumping me, she has always done this jumping from one relationship to the next with very little time in between. But even so she said she loved me how could anyone move on so quickly its like i meant nothing?

Im confused as to the why i miss her, when i know I'm happier without her and confused as to why someone would do this? She openly said i was the kindest person she ever met, then proceeded to sleep with someone else?

I admit I'm partly to blame i nearly lost my life one night ended up in hospital which stressed her out so she started sleeping round some guys house every night which made me nervous and needy which pushed her away to cheat on me and leave me.

The weird thing is i wouldn't change a thing that happened I've become a stronger person in so many ways from having gone through this, and i feel kinda proud about my, i managed to keep my head above water when she cheated on me and tried to use my friends to get back at me and I survived :D