failure motivation leads to heavy resentment

i would guess in any separation or divorce there are many stages of emotion. I am at the one where i basically resent anyone who shows me any type of caring. i was treated like i didn't matter by my estranged in so many ways. this effects me not only when those who do care about me show it or if i see a show or story in the news about how to keep your love alive, it shows me so many simple things that i was doing and she just refused to do. this makes me wonder what motivation she had in this refusal and what the desired outcome would be. i'm of the mind to believe she had very vindictive motives such as what would make me hurt worse and for the longest time. this makes the hatred and resentment worse.
i also wonder why, for so many years, i was like the cartoon i recall of Daffy Duck loading a black powder rifle and it going off in his face. each time it would go wrong he would go running back saying "I know what I did wrong!!!" with a sense of hope and a hunger to get it right. the saddest part for me is what makes the cartoon funny. The little mouse hiding down by the trigger, pulling it to make the gun go off in Daffy's face. i would set up so many safeguards or try so many different methods of righting our relationship. she would have something to say each time, like i simply needed to make more money or if she had to go to work, she'd go home to Missouri. I was expected to come up with the fix for all our woes and when i would
she'd sit back on her laurels waiting for some small part to make everything blow up in my face. i was not perfect and would, most of the time, go off on her. the fighting would lead me to apology and a new fix to insert and try.
after 15 years of this, I feel i haven't the emotional fuel left nor the motivation left to be of use in any relationship. this really hurts, as for most of my life, i have either been married or trying to be in a relationship.
I have no idea how to do this with no failure motivation, but i guess i will figure it out in time.