Ditzy:
In my case having a husband that controlled everything in your life from what time you got up in the morning to the time you went to bed is enough to make spite a very strong thing.
I was his "trophy wife".
I had to dress to the nines any time I went out with him and even if I went to the grocery.
If I failed to do exactly as he ordered he would slap me around and call me horrible names.
I doubt any of you ladies here would put up with that.
My spite was not really self harm to me but to his ego.
I knew it was temporary.
Eh, what do I know? I've never been in an abusive relationship. My mom raised me in one, but I handled it by holding a steak knife to his throat.
That said, I was talking more about OP, who has since deleted her post.