Having part of it removed for now is fine, because it is what was keeping you from having a normal bowel movement, you actually had a partial bowel blockage
due to the size of this polyp. If you had suffered a total blockage
you would have required emergency surgery. Polyps tend to bleed, but if you're bleeding a lot, call your GI. Since it was benign before, I assume it is again? I would opt for surgery to be sure that it is removed in it's entirety.