“And I say unto you, Whosoever shall put away his wife, except it be for fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery.” (Matthew 19:9) (KJV 1900)
On the surface it appears Jesus approves of remarriage if we divorce our spouse on grounds of adultery. But how can this be? The innocent wife, divorced from an adulterous husband, commits adultery when she remarries. And the man she marries also commits adultery.
here's the break-down.
Husband 1 commits adultery by marrying wife 2 who also commits adultery.
except clause does not apply because:
divorced innocent wife 1 also commits commits adultery along with husband 2 when they marry.
Back in the day they killed adulterers so the except clause would pertain to this allowing remarriage of the innocent.