OT, thanks for commenting on my sitch. I definitely appreciate your advice.
I can't figure out, however, how my FIL's breaking his promise to me and then deliberately doing something that he knew would upset me ... well, that just doesn't sound like "best interest in mind" to me. I agree that W isn't sentimental about the bed -- I am sentimental about it, however, and it's no good just telling me to get over it.
I'm not going to disagree with your assessment that it is better for W and me to stay apart right now, because I don't really disagree with it. That's not the point. The point is that it isn't "in my best interest" for him to break his promise to me without a discussion and for him to deliberately hurt me.
