What's wrong with me?

My alcoholic ex decides to come over to my place unannounced after a long while because I changed my number and he had no other way to contact me. Of course I let him in, I'm starting to question my sanity now. I've always had a delayed response maybe I'm high functioning autistic because I can never set boundaries even well into my 30's. He's sleeping on my sofa now and he promises to be my prince charming and knight in shinning armor. I want to ask him to leave but I feel bad. Why should I feel bad, I have built a good reputation in my neighborhood and I don't want to be seen around with a drunk. Am I a bad person for not wanting to be seen with him. He's very impulsive and he stumbles around drunk. Am I un humain for wanting him to leave after I never invited him over. He claims to love me after all these years, but I left him long ago because he is disorderly. I'm always taken advantage of because of my kindness but lately even I'm starting to think I'm stupid or rather on the slow end of the trail. How should I ask him to leave