You ask, "Why does he not?" Because the Lord was a witness between you and the wife of your youth, to whom you have been faithless, though she is your companion and your wife by covenant.
Did not one God make her? Both flesh and spirit are his. And what does the one God desire? Godly offspring. So look to yourselves, and do not let anyone be faithless to the wife of his youth.
References for Malachi 2:15
For I hate divorce, says the Lord, the God of Israel, and covering one's garment with violence, says the Lord of hosts. So take heed to yourselves and do not be faithless.
References for Malachi 2:16