I'm sorry to hear that he's said this, I know you are trying. This comment of his seems so contradictory though "He told me that sleeping in the bed was a sign of my commitment, that he wanted to see commitment from me before he would accept me back in the bed."
What type of commitment did he expect? Did he ever communicate to you WHAT he needed to see from you? I know so many betrayed spouses say they need to see remorse, but even they don't know EXACTLY what that remorse needs to looks like, so that makes it tough for the wandering spouse to show them the remorse they need.
However Heather, if he...after this much time has passed, cannot commit to doing what it takes to save your marriage with you...then there's a good chance he won't get past things at all. He's using the "bed issue" as an excuse IMPO.
