OK. I could be wrong, but I think since he's got 23 years or so on you, he thinks he can play you and get away with murder doing it. So far, he's done just that, and is probably having a ball.
Now with that said, I'd still call his behavior , (especially for a 45-yr-old), pretty f**kin unstable. If it were me, and I'm glad it's not, I'd give the landlord notice, and get the hell out. If you kick him out, (and he actually
GOES), he still knows where you live. I wouldn't trust him not to do something really harmful to you when you're least expecting it. Sounds like the type to hold a grudge, and if he thinks you were wrong to kick him out, and gets really pissed .... who knows? Better to be safe than to be in a hospital bed in traction.
Also, you are way too young to have this kinda crap be the most important thing happening in your life. (sounds pretty time consuming). MOVE ON, and start having fun, for God's sake. Life's too short.
Good luck