What happens by law to the man who is married and gets a wanother woman pregnant

Child support at the very least.

Divorce and alimony to the current wife if she walks on you for another.

Basically, kiss your spare money and discretionary spending good bye.

The man will have to pay child support.

If the wife wants a divorce that can happen also

Let me put it this way. Bye Bye
Lexus and wife. Hello Daddy and
And baby. It isn't the baby's fault.
Two people who couldn't control the old hormones. When you play you pay.

a wanother woman

Nice malapropism (http://en.wikipedia.org/wiki/Malapropism). :D

The only time the equation can change is if the "other womean" is also married. It can complicate things as far as the law is concerned. But if its straight up married man and single woman it goes as the others have stated.