Ok, it must be like a soap opera because soap operas confuse the heck out of me and you've got me baffled.
So, you were supposed to move in with 2 different guys? The one knew about the other one but that's okay because they are seeing others but now you're upset because the one you spoke to on the phone said that he was on a date.
I don't get what the problem is if you knew he was seeing other women as you're seeing other men.
If you're not trying to complicate your life, intentionally then it sounds like one or two things are happening or perhaps both at the same time...
1) You're insecure and giving yourself insurance by giving yourself more then one option to fall back on and in giving yourself that insurance you're making the men in your life feel insecure and needing to take out their own insurance to protect themselves from getting hurt.
2)You're rushing into things with either or both of these two guys because you're desperate to get away from this house you hate living in.

Have you thought about seeking out a female room mate until the romantic aspect of your life becomes a little more sturdy?
It sounds to me that you may need to take a step back. You may be wigging these two guys out because you don't seem to know what you want.
If someone was planning to move in with me but looking at his other options with another woman-I wouldn't feel so great about that.
I don't know if I understood the situation. If I've misinterpreted then I apologize. I'm really trying to help and not hurt.
(((((Yack))))))