From personal experience I would strongly agree. Separation helps with perspective, but its a huge loss of DB opportunity. Besides your W is quite mentally ill and you may want to see her in this light. Would you abandon her if she were physically ill?
I'm certainly not planning on abandoning my W - I totally agree that she has problems and needs support, and I plan to continue to support her in whatever way I can.
We're going to be separate again, probably after this coming weekend - I get the keys on Friday and W is pushing for me to move in over the weekend. So, as far as DBing goes, I've got this week to do it in her presence, but I need to start doing something different once we are separate (as other people have suggested). My plan is not to write off my W and start hunting for someone new - I just need to start doing more GAL activities, which includes meeting some new faces and doing new things. If W wants to spend time with me, I'll gladly accept, however I'm not going to do as much initiating as I have in the past with her.