I feel for you. I also collect books, try to read most of them, but it is hard to not have them with you. Many years ago I needed some money so I took books to Powell's in Portland to sell them. This was not a good thing for me as I had a real good bought of depression going. Started having suicidal dreams, I got over them, actually I turned them into papers fora writing class I ended up taking. That is another story. Went I got back on my feet I went back to Powell's to see if I could find them, Some I did, but I ended up finding more that were on different subjects. I actually found another section in another building. I realized that there are some that I would like to take to the grave with me so I will have something to do. I think what I am trying to say is that life goes on and there are many experiences to come. More books to get. I hope this helps.

Do not part of them... the knowledge you got from them. Keep them until you are gone. Keep them. They are part of you after all via the knowledge provided.