My husband's pain

As hurt as I am I try to take a little while each day and think about my husband's feelings.  What is he going through?  Does he hate himself?  Does he not think about his affair and what he did to his family because it hurts too much?  Is this why he doesn't want to talk about it with me even though I want to and need to?

I mean, a man doesn't do this to his family for nothing right?  What was going on in his head at the time?  During that week of "talking" to her (aka lusting after/fantasizing about a life with her) leading up to the kiss what was going on with him?  How could he do this and not think about his wife and kids even once?  He must have had extreme stress and pain of his own to do this.  Had to of.  Because a happy person doesn't do this to their family.  He was clearly not a happy person. 

I am so incredibly sad that my husband wasn't happy.  Really neither was I but in my head it was all external factors with money issues and time issues that was making me unhappy so I was "okay".  I knew there was an end to the unhappiness.  He himself and the family we made made me happy.  That was enough.

I hate even now today he seems so incredibly unhappy.  He's quiet.  He's tired.  He hates commuting.  He hates being in his car.  He hates where we live.  He hates the stress of our 3 year old being a 3 year old.  Our infant constantly cries and I can't really think of a moment where he seems to be enjoying her.  I remember seeing such joy and love in his eyes when he held and looked at our son at that age but I haven't seen that with our daughter.  I know he loves her...but it seems different.  

What does he love?  I want him to love life.  I want him to love coming home to us.  I want him to look forward to tomorrow.  He doesn't and it kills me.  I never wanted my husband to hate so much. 
 
And I don't know what to do.  I don't know how to help this.