If he Only Had a Brain, and Some Courage and a Heart....

For the past 10 years I  begged my husband to consider having a child - but he adamantly refused.  He said that he had no interest in being a father and did not want to be tied down.  He said that people turn into idiots when they have children.  I went to counseling to accept it, he would not go.  I made the decision to stay in my marriage, because I loved him.  I am basically now too old to have children.  Apparently what my husband and this child/woman have in common is the fact that she is pregnant with his child.  And he is thrilled.  They are also engaged, which is especially odd because he is still married.  What kind of man would do this?  And what kind of girl would want a 51 year old man (30 years older than herself) who would desert a faithful and loving wife of 22 years?