Why some men avoid taking responsability ?

First after dedicating 18 years on a marriage ,he cheats a do eveything on the book to damage the marriage ,he walk out to live with the other woman who persue him nonestop at his work ,inviting him to her place in Ny making him get an apt. in m. for the both of them etc. ect. ,and now is angry for paying child support and alimony ,he is in debt up to his neck not mentioning having other people suing him and just because he is paying this $ he acts like I'm the biggest ***** in this world instead of recognizing that he has to pay for all he did to his children I his wife .By the way He has never apologyze for anything .Why can he recognize that this woman is manipulating him to think his ex and his children are a ponisment instead of the other way around?Is she so unhappy that needs to act this way ? there has to be something wrong with both of them.