This is what I did to our churches a few years ago. I asked the ladies groups for all their unused/unfinished projects and unwanted fabric to distribute to people here where these things are expensive. So, mostly I got kits of crewel embroidery, cross stitch and various things--and some truly ugly fabric (and some wonderful stuff).
Anyway, I think it helped the ladies who could unload their stuff and I was able to distribute a very large amount of it. Also, I finished up every single double knit (yuck) quilt top that was sent me and believe it or not, they have all been chosen by ladies who want them. I did make them into comforters and not quilts, though.
So, if you do finish your quilt top and don't want it, give it to someone who does want it and they can finish it and use it. Or you can try to sell it on Ebay or here on the thread of the sale items. Of course, you could donate it, either finished or unfinished (making sure it is wanted, of course).
But you could put it away for a year now, first, and see if the break will help. A king or queen is a big quilt. I put my "The North" Cathedral Windows quilt away for 2.5 years because I was tired of it and it was such a big task. When I took it out this year, I finished it in a couple of weeks because I admired how beautiful it was. I'm so tickled with it now.