I read your whole post, all the while thinking about the questions Byron Katie asks about thoughts, and then at the end, it turns out you're drawn in that direction, too!
I would like to invite you to go through your post and ask the four questions about each of your beliefs, particularly since you were headed down that road already. The process might help you let go of all your story and let this guy go, with lots of love.
As far as him taking advantage of you, well, I guess you know he can only do that if you give him permission to. Maybe you'd like to give him permission to take advantage of you, which is fine. If not, how about letting him know that in order to let him go, you have to let his stuff go? Give him a reasonable deadline, say, one week, and let him know that if his stuff is still at your place, you have a date with Goodwill at noon on Deadline Day. Tell him that if he doesn't act to pick up his things, he can be glad to know they'll be going to a good cause. (but
you take the tax deduction
)
Let us know how things go.
Love,
Angela