How to create an immortal action hero, and don't forget the feminine side

When I sat down to write 'The Immortality Plot' I was determined to create a thriller hero with a difference. The original title of the book was 'Old Habits Die Hard' and I am still attached to that title. I think I'll use it for a follow-up thriller.
I had a pretty impressive roster of heroes to inspire me: Jack Reacher, Jason Bourne, Jack Keller, Father Brown (who, you may ask? Do some research).
I suppose I modelled a part of his personality and background on my own and then went into overdrive with the rest. He is Irish-American, I am Anglo-Irish. We are both six feet five inches but he is a lot younger and fitter than me. He has a hankering after spiritual truths, metaphysical experiences and he is a consummate killer. I conform to the first part of the description. But Mike Delaney is now a reluctant killer. He was trained in the US army, then went undercover for the Hong Kong Police. Later,  his HKP buddy Bob Messenger started a website called confess-confess to give ordinary people a voice and a chance to redress the imbalances of their lives when faced with faceless criminals.
One aspect I overlooked or just wasn't aware of came up in one of the Amazon reviews. It said that Mike Delaney stood out because he wasn't frightened to embrace the feminine side of his nature.
That threw me a little until I thought about it. I discovered that this too was an aspect of my own nature transposed to my alter ego.
And I realise as I embark on a new Mike Delaney thriller tentatively titled 'Good Girl Bad Girl' that it is a vitally important element to retain in order to build the Mike Delaney character and world view into mainstream and hopefully successful book series.
Below I am pasting the latest Amazon review, not the one with the feminine point but still extremely gratifying.
Mike Delaney was a hard, take no prisoners type of guy - until his wife was murdered and their baby died with her. He had been nearly murdered in China while working as a cop; worked before that for a group that didn't have a name and survived but Maria's murder? That did him in. He left their house for a monastery high in the California hills, where he meditated, practiced Tai Chi and other arts until time came he had to do something else. Find the murderer of his wife.
\r\nShe had been a journalist with a home office he didn't intrude on but, after the fire he had sense enough to move what was left of her computer and files somewhere else until the investigation was done. Until the public's mind was distracted by the next big thing - The Priest. He took lovely young women, made them confess on tape to a myriad of sins and then put the tape in their mouths and killed them. His newest offerings had a cross-cut into their backs.
\r\nAll clues and other disappearances somehow lead to a charity funder called LifeForce International but how? Mike risks everything to find out and, at the end, the surprise is his. You have to read this thriller! It never stops surprising and making you think you've got the answer when, in fact, you've got no clue at all!