What excuse did Henry the 8th need to kill two of his wifes?

He tried both his wives for adultery (wives were Anne Boleyn and Catherine Howard - cousins as it happens). Adultery on the part of a queen consort is treason, punishable by death. Henry mitigated the sentences to beheading, he could have had them both burnt at the stake. Not that that excuses him. read more

So I would say Henry is responsible for two deaths certainly: Katherine of Aragon and Anne Boleyn. Jane Seymour died of disease from pregnancy. She never had a strong constitution. Henry did send Katherine Howard to her death, but she committed a crime against the King with her adultery. She was very young. read more

Henry VIII did not, personally, kill any of his wives. His second wife, Anne Boleyn, was tried, convicted and executed for treason, adultery and incest. The charges were almost certainly untrue. His fifth wife, Katherine Howard, was tried, convicted and executed for treason and adultery. The charges were almost certainly true. read more

To be fair, however, Henry only directly killed two of his wives; #2 Anne Boleyn and #5 Catherine Howard, and maybe indirectly had a hand in the death of #1 Catherine of Aragon, but he didn’t kill the other 3 of his wives. read more