Sounds like he is still feeling very guilty and is looking to you for constant reassurance and support. Are you up for it? It's a challenge, being 'responsible' for someone elses happiness. Done in the right way, I think you can give him a boost of smiles and confidence and then let him fan the flames to keep it going. OR - How's he been sleeping? Could be he was just having a temporary down day too.
Live your life while you are still living. Riding the trail less traveled.