This is the only part I don't like:
When I feel up to it I will contact you back.
Why bother to say this?
- you know you don't want to and most likely you're not going to.
There is a big difference between ending a relationship
and delaying/putting someone off with empty promises. As much as I dislike the parasitic woman, there is no reason to give false hope. AND - it leaves the door open and gives her a reason to periodically contact you "just to see if you're up to it".
Ending it means exactly that.