The first thing you should know is that THIS ISN'T YOUR FAULT. You cannot choose your parents. You have no control over who you are born to in this world. Some babies are born to drug addicted parents & they are rudely called "crack babies" because they are literally addicted to crack from the moment they are born. Do you think that these babies willingly chose to have parents like this?
Your dad is a scumbag. Plain & simple. The fact that he told you he disowns you & he spends more money on his wife than he does on his own child says a lot about your father. He sounds like a very selfish man who is probably a narcissist. A narcissist is someone who is in their own world, only cares about their own needs & cannot sympathize too well with others - not even their own children. There are 11 important things that I want to point out to you that might help you to see things for what they are but I don't know if it will allow me to post all 11 points I wanted to make. I'll try:
Your dad and his wife are selfish douchebags:
1. It seems like your dad & his wife have a mutually beneficial relationship. Is she younger or more attractive than he is? Maybe she's a gold digger. I know this sounds gross to you because you are his daughter but there are so many relationships like this where the wife is helping the husband to meet his physical (sexual) needs and where the husband is helping the wife meet her financial (gold digging) needs. It's possible they both got married for selfish reasons & if so then their marriage will probably not withstand the test of time. But this doesn't give him an excuse to come crawling back.
It's possible that they are (unfairly) using your teen years against you:
2. You're 17. Being a teenager is a tough stage in your life. Most teens - both male and female - go through a stage where they tend to be moody and sometimes parents have a hard time dealing with this. But most parents don't disown their kids just for being teens. This is just a life stage everyone goes through. Maybe your dad's extreme selfishness allows him less patience than most other dads would have. And maybe his wife sees you as nothing more than a bratty teen who threatens her source of money and could be possibly fueling any of your dad's negative feelings towards you & making them bigger. But this is a time in your life when it's especially important that he be there for you. And he's failing miserably. No matter how bad you might misbehave, it is no excuse for the way your dad is being.
Maybe he's avoiding financial responsibility:
3. On that same note, it's possible that he's trying to distance himself from you because you're coming of age soon. When you turn 18 he no longer is financially responsible for you. Maybe both he & his wife don't want any of his money going towards your college education, car, clothes, or well being. This could be your father's way of showing you he doesn't want to spent any more money on you. The VAST MAJORITY of dads that are present in their children's life support their kids through college & even after college graduation while they are learning to stand on their own two feet. Also, the majority of dads help out their adult kids in times of financial problems. So if he tells you that he no longer owes you money when you turn 18 just remember that this is more of his selfish B.S. and not the way a good dad is supposed to be. But there's nothing you can do about that.
You are placing incorrect blame which won't help your situation:
4. You say that "I feel worthless & no reason to live anymore. That b*tch took everything I had away." That beyotch took nothing away from you. Do not blame this woman. If anything she is just letting you see your dad for who HE TRULY IS. Perhaps she's making things worse but she never held a gun to your father's head and told him to be a bad father to you or else she would shoot him dead. Open your eyes. She sounds like a terrible woman but all of this is your dad's fault.