I was on the fence right up until the moment I wasn't. I asked my XABF to leave my home even though I knew he did not have anywhere to go, or enough money to rent his own place. I decided he had survived somehow for many years without me taking care of him, and he could do it again if he had to.
Life is too short. If I kept waiting, he would never ever choose to take care of himself, to learn to be self-reliant, to seek out a better way of living. Which is not to say I did him a favor by kicking him out, but you know -- he found a place to stay for a couple of days before working out a more permanent situation.
When I realized that guilt was the only thing keeping me tied to this person, I knew I had to examine that for myself. I couldn't do that while I was more concerned with being responsible on his behalf than on my own.