MerMaid, your last post is all about him - how you want him to act, what you think is wrong with him etc. You're not happy cos you don't think he's happy - your 'spidey sense' is tingling and you know how he feels despite his words and actions!. You really need to take the focus off him and put it back on you. You cannot rely on someone else for your happiness.
Trust him - he's a grown up who can make his own choices. I've struggled with depression most of my adult life. Just like alcoholism, no one else can make me better, the three C's work here too! I have to change how I think myself. I can get help from counsellors and other professionals (anti depressants saved my life) but I'm the one who has to work on it alone. If he is unhappy, then he has to work out for himself what will make him happy. You worrying at him and trying to 'make' him happy won't help. My STBXAH used to pester me like this - not that I'm saying you're pestering him, I'm just getting flashbacks! He eventually tried to control what I thought and felt, undermining my self confidence and ability to work through it on my own. You cannot control him. You cannot change him. The only person you can change and control is YOU!
I really do recommend you read Co-dependant No More. I think you will be surprised at just how much of it you will relate to!