Having doubts in Gods existence is because you are lacking the Truth, As a Christian you should study and read His word DAILY.  It i bad that you think that God doesn't exists because in The Bible it says that He is The Way The Truth and The LIFE. If there is a Heaven then there must be a Hell, same as if there is Good, then there is definitely Bad.

  Take this as a Encouragement; x

As a Christian, i say that you should Love God, and God will bless you with a willing heart to Love your wife and to be a great husband. :)

I believe that our souls last forever. Our flesh dies out but our souls remain forever :)