Would it be possible to have a sort of "temporary separation"? Where you separate you and your daughter from the situation (maybe living with family, if that's possible) until your fiancé hopefully returns to himself. That way you're protecting yourself and your daughter, but not walking away.

It appears that the stress (or other emotions) involved with him losing his job has been wearing on him and he's unfortunately taking it out on you. Hopefully him getting another job will "change" him back. But this behavior is worrisome…it might be useful for him to see a psychiatrist because either his personality has suddenly changed or he's unable to cope with frustration etc. in a healthy manner (meaning that this could happen again the next time he's laid off or something doesn't go his way).

I can't personally tell you why he's acting this way or the best way to help him but hopefully a doctor will. This may "back him into a corner" in a way, but I can't think of a better solution—at least this way you're not really turning your back on him, you're just putting some temporary space between you and him. Hopefully, if someone else has a better idea they'll post. Either way, good luck resolving this!