I'm inclined to think that as far as the "why"... well, there are a million threads describing a million commonalities among people. Some identifying with one, some identifying with more than one, but all woven together into the tapestry of life. And I think it's this tapestry which should be admired, rather than the threads which went into it.
Although I'm feeling rather emotional today, so I'll address the OP with regard to my own experience.
My father was... well... a grade-A miscreant. The sum total of everything bad in this world. He left me and my two brothers to fend for ourselves at a very young age, and my mother... well... she was an emotional wreck after the whole thing. That being said, it was the best thing he ever did. He was abusive, violent (physically and sexually, but I will say no more of that here), lazy, quick to blame the rest of the world for his shortcomings... and, yeah, basically an all round bad egg. So him leaving was, overall, the best thing that happened.
Because of this, I guess it could be said I developed a closer bond with my mother. Simply by virtue of her being the only immediate parental figure I had. However, in that time she hated herself, and blamed herself as a woman for caring about him. She attributed all of her weaknesses on being female, and tried to instil that in me. That I had to be strong because it was in my genes. That I had to take control of situations because I hadn't been born "some stupid, naïve girl who didn't know better".
Not to mention my grandfather. I idolised him. I mean properly idolised him. He built his life up from nothing. One of ten children in the 1930's, he was the typical "Pull yourself up by your bootstraps" guy. Made and lost a fortune because people played him for a fool since he was too nice to others and gave them whatever they wanted. He stepped up to the plate and became a sort of fill in father figure for me. And probably the best one I could have ever hoped for. Had I been a man, I would have wanted to be like him. Or have his traits. I guess I still do, in a way.
If anything, all the signs were pushing me towards being like my grandfather, and wanting me to be like he was. Part of me will always try to be, because he was one of the best people I've ever known.
But... uh... yeah... I guess what I'm saying is that given my relationship, or lack thereof, with my father... I don't think it was my relationship with my mother or anyone else which caused me to be who I am. I think rather I found myself and acknowledged the aspects of people close to me along the way.