It appears that he may be having a crisis from what you've posted. MLC's main ingredient is depression. Depression is about the past and anxiety is about the future. Confusion, acting out, being the mirror image of the person you once knew (exact opposite), spending, drinking, experimenting w/drugs, affairs and sometimes no affairs, but focused on work, a sport, appearance, etc., the list can go on and on.
Everything to him will be seen through very dark glasses and you will become public enemy number one to him. He's unhappy w/his life, the world, friends, family, work and you. There's nothing you can do to convince him that it is him and the depression talking.
It's good that he's seeing someone professionally and is reading the book(s) that the professional is recommending, however, this doesn't mean that he'll snap out of it any time soon. It takes years to build up to the crisis and it will take a few years for him to work thru it and hopefully come out the other side a more mature, responsible man. Just remember, you didn't break him, therefore, you can't fix him.
For now, keep the focus on you, watch and protect your assets and definitely keep tabs on your finances, since he's going to be spending money, i.e., quite a bit if he's in crisis.
