you are NOT a piece of crap and I'm not even sure why you would think that about yourself from everything you posted.

Your husband sounds like a piece of crap for how he is treating you.

I'm not sure about the whole posting on Craigslist for a friend thing, but i've only used it for dating or selling things -i just never thought about using it for that. If you want to have a friend, you should be able to have a friend - if your husband is having a problem with this, it's out of his own insecurities. He's playing on your sympathies - HE needs mental help if he's threatening suicide. you might want to get help so you realize you deserve better treatment than you are getting. And if the house is in your name, kick the man out.
Good luck!