I'm sorry you had a rough date. It's very possible your son simply had the dream because he saw a spider on tv or in a book or in the yard. I'd stop torturing yourself on that one if you can.
As for your question to me, I think you can "conditionally validate" your husband's comments. For example, you can say that it would be a good decision to come home if he is willing to do this and that. That the only time he makes bad decisions are from this and that. Basically telling him that you'll let him back into your life IF he changes, but that IF he changes you believe the two of you and the family will be happy together.
I wager however, that he isn't looking for this conditional validation. He wants it to be easy and that he dosen't have to answer for the things he has done to hurt you. Remember, until recently he really hasn't had any consequences because you have taken him back and still loved him. He is still learning this new behaviour and this one isn't as simple for him. He is sort of like a toddler right now testing you to see what he can get away with. You know how to handle those children right BBJ?