Marriage
chollida1: I think the biggest problem is that both a marriage and a successful company require a lot of work.  And when push comes to shove you sometimes have to let one suffer inorder to help the other.The guys you mention above all fit into the work is their life mold where they throw themselves into what ever they were doing.  This won't surprise anyone but that doesn't really endear yourself to your partner.I know a very successful entrepreneur who has been married 4 times now.  Each one of his wives couldn't stand coming second to work and I'll bet that each one went into the marriage thinking that this time it would be different, that they could change him.