If your spouse is truly in MLC, he's not going to want to listen to a word you have to say. The more you push for answers or talking about the relationship, the more he's going to distance himself and what he has to say may not be what you want to hear. Don't give him any more justification for leaving...just leave him be. Allow him to work on himself and he can't do that if he's trying to figure out ways to side step you and your "talks". The best thing to do is give him all the space he needs.
Dig very deep for patience because this is not a sprint...but a marathon and it will not end soon, but could take years for him to work through his issues. Again, just leave him totally alone and allow him to come to you when he's ready. The more you listen, the more you will learn from him.
Keep the focus on you and live your life as if he may not return.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.