Agreed. but it goes way beyone that.
On a scale of 1-10
if 1 being super nice guy and 10 being ultra asshole. He was possibly a 2.
Any such dude, a woman will take advantage of without mercy. Women want to be challenged, and excited. Additionally, they are emotional creatures and as a man you need to take her throught a range of emotions and they will love you more for it. More than likey he possibly never took her through disappointment, sadness, anger, fear, hurt. And I use the work hurt carefully here. I would assume he only took her through, 'comfort,' suprise, and love, joy.
Moreover, anyman who is too nice will continually get walked over. He was alway extra nice and no woman wants that, she may tell you that she does because she is socially programmed to say so but she gets bored after a while. We [humans] prefer the "better" emotions in life but we are all thankful that our parents disciplined us when we were children because we learned the value of discipline as an adult. Such it is with all relationships i.e relationships between man and woman, woman and child, law and citizen etc. We must reward and punish/train each other alike for good and bad deeds. He only rewarded her, he never punished her for 'bad' deeds.
In theory, a woman wants a strong-decisive-alpha -leader and nothing about that guy says any of those qualities. Only thing is that he was a good provider. Ask yourself why does the sterotypical house wife cheats on a man who works many hours to put food on a table, even though he is a so called good man? It is human nature to be bored by routine and he is a boring routine within himself. If a man/woman has no bounderies with their partner, said partner will walk over them.
the key is balance.