HI Luna and welcome to SR. I am sorry you are having to go through this.Sounds like your husband is an addict. Also sounds like cross-addiction to me with the emphasis on pills. Only he can decide if he wants to get right and clean and work on his addiction and your marriage. Until he makes that decision your relationship is at a standstill. However, you can work on YOU by going to NarAnon meetings or even Alanon if there is no Naranon in your area. Work on yourself and you will feel much better.
He also sounds like he has some fairly serious mental problems. Have you seen his medical records from when he was in the mental ward? If you can get them it might give you an idea about what's REALLY going on in his head. You probably can't just get them, he will have to request them (or, just call them, have them FAX a form to you that he can sign and then have them mailed to your house.
Plus, if you are separated it means that you may end up divorced later in which case those could be useful.